What is living? Questions in English

(C) Statement $(a)$ is incorrect because reproduction and growth are mutually exclusive events in the majority of higher organisms.
Statement $(b)$ is correct because metabolism (the sum total of all chemical reactions occurring in a body) is a defining feature of all living organisms without exception.
Statement $(c)$ is correct because cellular organization of the body is the defining feature of life forms.
Statement $(d)$ is incorrect because consciousness (the ability to sense the environment and respond to environmental stimuli) is the most obvious and technically complicated defining feature of all living organisms.
Therefore,statements $(b)$ and $(c)$ are correct.

(C) species is defined as a group of organisms that can interbreed under natural conditions to produce fertile offspring.
This is the fundamental biological concept of a species,known as the Biological Species Concept.
While members of the same species often share similar habitats or lifestyles,the defining characteristic that separates them from other species is their ability to interbreed and produce viable,fertile offspring.

(D) Living organisms are considered open systems because they continuously exchange energy and matter with their external environment.
They require a constant input of energy (e.g.,sunlight or food) to maintain their metabolic processes and structural organization.
Since they exchange both energy and matter with the surroundings,they cannot be classified as closed systems.
Therefore,both the Assertion and the Reason are incorrect.

(D) Assertion is incorrect because the number of cells in a multicellular organism is generally directly proportional to the size of the body,not inversely proportional. Larger organisms typically have more cells.
Reason is incorrect because not all cells are alive; for example,xylem vessels and tracheids in plants,and cork cells,are dead at maturity.

(N/A) Earth hosts a vast diversity of plants,animals,and microbes,all varying in size,shape,color,habitat,and other characteristics. With millions of species existing,it is impossible to study each one individually. Therefore,scientists have developed systems of biological classification. These systems are based on rules and principles that facilitate the identification,nomenclature,and classification of organisms. By grouping organisms based on similarities and differences,classification reveals the evolutionary relationships between them and makes the study of life organized and manageable.

(D) The diversity of living organisms is truly remarkable.
Living organisms are found in a wide range of extraordinary habitats,including:
$\Rightarrow$ Cold mountains
$\Rightarrow$ Deciduous forests
$\Rightarrow$ Oceans
$\Rightarrow$ Freshwater lakes
$\Rightarrow$ Deserts
$\Rightarrow$ Hot springs
In conclusion,living organisms are found in almost every place on Earth.

(N/A) The living organisms that create a sense of wonder include:
$1$. Migratory birds that travel thousands of kilometers.
$2$. The predatory behavior of sharks.
$3$. The complex social behavior of bees or the blooming of flowers.
These organisms teach us about:
$1$. Ecological conflict and cooperation among members of a population and among populations of a community.
$2$. The intricate molecular traffic and metabolic processes occurring inside a cell.
$3$. The interconnectedness and complexity of life on Earth.

(B) The study of living organisms leads to two fundamental questions:
$1$. The first is a technical question: 'What is living as opposed to the non-living?' This seeks to define the characteristics that distinguish living organisms from inanimate matter.
$2$. The second is a philosophical question: 'What is the purpose of life?' This seeks to understand the meaning or goal of existence.

(N/A) The important characteristics of living organisms are:
$1$. Growth (increase in mass and number of individuals).
$2$. Reproduction (production of offspring).
$3$. Metabolism (biochemical reactions occurring inside the body).
$4$. Response to environmental stimuli (consciousness).
$5$. Ability to self-organize.
Detailed explanation:
- Growth: All living organisms grow. Increase in mass and increase in the number of individuals are twin characteristics of growth. In plants,growth by cell division occurs continuously throughout their life span,whereas in animals,it occurs only up to a certain age. Growth is not a defining property of living organisms because non-living objects (like mountains or boulders) also increase in mass by accumulation of material on the surface,whereas living organisms grow from inside.
- Reproduction: Living organisms produce offspring similar to themselves. While it is a characteristic of life,it is not a defining property because some organisms like worker bees,mules,and infertile human couples do not reproduce.
- Metabolism: The sum total of all chemical reactions occurring in a living body is metabolism. It is a defining feature of all living organisms without exception.
- Consciousness: The ability to sense the environment and respond to environmental stimuli is a defining property of living organisms.

(N/A) $\Rightarrow$ Living organisms are self-replicating,evolving,and self-regulating interactive systems capable of responding to external stimuli.
$\Rightarrow$ The unique characteristics of life arise from the interactions among the components of the organism.
$\Rightarrow$ Properties of tissues are not present in the constituent cells but arise as a result of interactions among the constituent cells.
$\Rightarrow$ Similarly,properties of cellular organelles are not present in the molecular constituents of the organelle but arise as a result of interactions among the molecular components comprising the organelle.
$\Rightarrow$ These interactions result in emergent properties at a higher level of organization.
$\Rightarrow$ This phenomenon is true in the hierarchy of organizational complexity at all levels.
$\Rightarrow$ Therefore,we can say that living organisms are self-replicating,evolving,and self-regulating interactive systems capable of responding to external stimuli.
$\Rightarrow$ Biology is the story of life on Earth and the story of evolution of living organisms on Earth.
$\Rightarrow$ All living organisms—present,past,and future—are linked to one another by the sharing of the common genetic material,but to varying degrees.

(A) $1$. Living organisms (animate) exhibit intrinsic growth,meaning growth occurs from within due to cell division and metabolic activities.
$2$. Non-living objects (inanimate) exhibit extrinsic growth,meaning growth occurs by the accumulation of material on the surface (e.g.,mountains,boulders,and sand mounds).
$3$. Therefore,growth cannot be taken as a defining property of living organisms because non-living things also grow if we take surface accumulation into account.

(N/A) $1$. All living organisms,from the simplest prokaryotes to the most complex eukaryotes,can sense and respond to environmental factors.
$2$. These environmental cues include physical factors like light,water,and temperature,as well as biological factors like other organisms and chemical factors like pollutants.
$3$. Humans are the only organisms aware of themselves,i.e.,they have self-consciousness.
$4$. Thus,consciousness is a defining property of living organisms.

(N/A) Self-consciousness is the ability of an organism to be aware of itself.
$1$. All living organisms,from the simplest prokaryotes to the most complex eukaryotes,sense their environment and respond to external stimuli like light,water,temperature,and other organisms.
$2$. However,self-consciousness,which is the awareness of one's own existence,is a unique feature of human beings.
$3$. Humans are the only organisms that are aware of themselves,have thoughts,and can reflect on their own actions.
$4$. Therefore,while consciousness (response to external stimuli) is a defining property of all living organisms,self-consciousness is restricted to humans.

(N/A) $\Rightarrow$ The unique phenomena of life in living organisms are possible due to interactions within their bodies.
$\Rightarrow$ The properties of tissues are not present in the constituent cells but arise as a result of interactions among the constituent cells.
$\Rightarrow$ Similarly,the properties of cellular organelles are not present in the molecular constituents of the organelle but arise as a result of interactions among the molecular components comprising the organelle.
$\Rightarrow$ These interactions result in emergent properties at a higher level of organization.
$\Rightarrow$ This phenomenon is true in the hierarchy of organizational complexity at all levels.
$\Rightarrow$ Therefore,living organisms are self-replicating,evolving,and self-regulating interactive systems capable of responding to external stimuli.
$\Rightarrow$ Biology is the story of life on Earth and the story of the evolution of living organisms.
$\Rightarrow$ All living organisms—present,past,and future—are linked to one another by the sharing of common genetic material,but to varying degrees.

(N/A) $\rightarrow$ $A$ ball of snow increases in mass,volume,and size when rolled over snow,but this increase is due to the accumulation of material on the surface from the outside (accretion).
$\rightarrow$ In living organisms,growth occurs due to the internal accumulation of materials and the synthesis of new protoplasm through cell division.
$\rightarrow$ Therefore,the growth of a snow ball is not comparable to the growth of living organisms because growth in living beings is intrinsic (from within),whereas in non-living objects like a snow ball,it is extrinsic (from outside).

(N/A) $\Rightarrow$ The world is composed of both living and non-living entities.
$\Rightarrow$ The fundamental difference between living and non-living objects is that all living organisms possess cells,which are the basic unit of life.
$\Rightarrow$ $A$ cell is the structural and functional unit of all living organisms.
$\Rightarrow$ Organisms composed of a single cell are termed as unicellular organisms,whereas those composed of many cells are known as multicellular organisms.
$\Rightarrow$ Living organisms exhibit characteristics such as metabolism,growth,reproduction,response to stimuli,and homeostasis,which are absent in non-living objects.

(N/A) Scientific research indicates that several animals besides humans possess self-consciousness. $A$ primary example is the dolphin,which is highly intelligent and demonstrates a clear sense of self. Dolphins can recognize themselves in mirrors and identify other individuals within their social groups. They communicate using complex methods such as whistles,tail-slapping,and various body movements. Other animals that exhibit signs of self-consciousness include chimpanzees,gorillas,orangutans,parrots,and crows.

(N/A) $\rightarrow$ An organism is said to be living if it shows certain characteristic features that distinguish it from non-living things.
$\rightarrow$ The following are the defining features of life forms:
$(1)$ Metabolism: It is the sum total of all chemical reactions occurring inside the body of a living organism. It is a defining feature because no non-living object exhibits metabolism.
$(2)$ Cellular organization: All living organisms are made up of one or more cells,which are the structural and functional units of life.
$(3)$ Consciousness: The ability to sense the environment and respond to environmental stimuli is a defining property of all living organisms.
$(4)$ Self-replication/Self-organization: Living organisms possess the ability to self-replicate and self-organize,which is a unique characteristic of life.

(N/A) $\rightarrow$ The total sum of all chemical reactions occurring in a living cell or organism is called metabolism. It involves the formation of various molecules and the breakdown of many others. All organisms,such as protozoans,algae,fungi,and bacteria,exhibit metabolism.
$\rightarrow$ Metabolic reactions can be demonstrated outside the body in cell-free systems,which are neither living nor non-living. Isolated metabolic reactions in vitro are,therefore,not living things but are surely living reactions. All biological reactions are highly specific,selective,and enzyme-catalyzed.

(N/A) $\rightarrow$ In human beings,it is difficult to define the living state. For example,patients lying in a coma,supported by machines that replace heart and lung functions,are brain-dead with no self-consciousness.
$\rightarrow$ Some of these patients never return to a normal life.
$\rightarrow$ They can neither be strictly called living nor non-living or dead,as they lack the defining characteristics of a living organism like self-consciousness,yet their metabolic processes are artificially maintained.

(N/A)

Whole Moong Dal	Broken Moong Dal
$1$. The whole seed is intact.	$1$. Seed is broken into pieces.
$2$. Seed is capable of carrying out respiration.	$2$. Respiration does not take place.
$3$. When given all favourable conditions,it germinates.	$3$. Unable to germinate.
$4$. During germination,it resumes metabolic activity.	$4$. Unable to resume metabolic activity.

We can conclude that 'whole moong dal' is a living entity because it contains a viable embryo capable of respiration,metabolism,and growth under favorable conditions. Conversely,'broken moong dal' is non-living because the embryo is damaged,rendering it incapable of respiration,germination,or growth,although it retains significant nutritive value.

(D) It is true that some properties of tissues are emergent, meaning they arise from the interaction of cells rather than being present in individual cells. Three examples are:
$1$. $Muscle$ $tissue$: The tissue as a whole is capable of contraction, but individual muscle cells (myocytes) only perform contraction through the interaction of actin and myosin filaments within the tissue structure.
$2$. $Skeletal$ $system$: This system is composed of bones and cartilage. $A$ bone is hard and provides structural support, but individual osteocytes (bone cells) are not hard in the same way; the hardness is a property of the extracellular matrix secreted by these cells.
$3$. $Blood$: Blood is a fluid connective tissue capable of transporting oxygen and nutrients throughout the body. Individual blood cells (like erythrocytes or leukocytes) cannot perform the function of systemic circulation independently; this is a property of the tissue as a whole.

(N/A) $\rightarrow$ In human beings,it is difficult to define the living state. For example,patients lying in a coma,supported by machines that replace heart and lung functions,are brain-dead with no self-consciousness.
$\rightarrow$ Some of these patients never return to normal life.
$\rightarrow$ They can neither be strictly called living nor non-living or dead,as they lack self-consciousness but maintain some biological functions through artificial support.

(B) In human beings,it is often difficult to define the living state.
For example,patients lying in a coma who are supported by machines that replace heart and lung functions are considered brain-dead and have no self-consciousness.
Some of these patients never return to a normal life.
Because they lack self-consciousness and are dependent on life-support systems,they can neither be strictly called living nor non-living or dead.

(N/A) $\rightarrow$ There is a physical (non-living) hierarchy and a biological hierarchy in the organization of a living body.
$\rightarrow$ In the physical hierarchy,various non-living components aggregate to form compounds,which finally enter the living world in the form of cells.
$\rightarrow$ These cells organize to form tissues,which form organs,and several organs combine to form an organ system.
$\rightarrow$ Finally,many organ systems organize to form a living organism.
$\rightarrow$ The properties of tissues are not present in the constituent cells but arise as a result of interactions among the constituent cells.
$\rightarrow$ For example,bone is a hard tissue that provides a framework to the body,but the individual cells present inside it do not possess this property.
$\rightarrow$ This phenomenon of interactions between various components of the body results in the hierarchy of organization.
$\rightarrow$ The various life processes are the result of this interaction and coordination.

(N/A) $\rightarrow$ The complexity in biological organization enables living organisms to be self-replicating,evolving,self-regulating,and capable of responding to external stimuli.
$\rightarrow$ All living organisms,along with their ancestors and descendants,are linked to one another by the sharing of common genetic material in the form of $DNA$,which is responsible for the expression of specific traits in organisms.
$\rightarrow$ Thus,Biology is the story of life on the earth.
$\rightarrow$ It is the story of the evolution of living organisms on the earth.

(N/A) $\Rightarrow$ There are millions of plants and animals in our world.
$\Rightarrow$ We know the plants and animals in our own area by their local names.
$\Rightarrow$ These local names vary from place to place,even within a country.
$\Rightarrow$ Hence,there is a need to standardize the naming of living organisms so that a particular organism is known by the same name all over the world.
$\Rightarrow$ Nomenclature is the system of naming living organisms in such a way that a particular organism is known by the same name all over the world.
$\Rightarrow$ Nomenclature or naming is only possible when the organism is described correctly and we know to what organism the name is attached to. This is called identification.
$\Rightarrow$ Identification aims at finding the correct name and appropriate position of an organism in a classification system.
$\Rightarrow$ The morphological and anatomical characters are examined for proper identification before assigning a scientific name.

(N/A) $\rightarrow$ Non-living objects also grow if we take an increase in body mass as a criterion for growth.
$\rightarrow$ Mountains,boulders,and sand mounds do grow by the accumulation of material on their surface.
$\rightarrow$ In living organisms,growth occurs from the inside.
$\rightarrow$ Therefore,growth cannot be taken as a defining property of living organisms because it is not exclusive to them.
$\rightarrow$ $A$ dead organism does not grow,which distinguishes it from non-living objects that may accumulate mass over time.

(N/A) Identification is the process of correctly describing an organism so that it can be named according to a standardized system of nomenclature.
The primary aim of identification is to determine the correct name and the appropriate taxonomic position of an organism within the classification system.

(N/A) $(i)$ Unicellular organisms are organisms that consist of only a single cell. All life processes,such as metabolism,excretion,and reproduction,occur within this single cell. Examples include $Amoeba$,$Chlamydomonas$,and bacteria.
$(ii)$ Multicellular organisms are organisms that are composed of many cells. These cells are often specialized to perform specific functions and are organized into tissues,organs,and organ systems. Examples include humans,plants,and animals.

(C) In unicellular organisms,growth and reproduction are inclusive events because they grow by cell division,which also results in an increase in the number of cells (reproduction).
Therefore,statement $(1)$ is correct.
Since unicellular organisms increase their cell number through cell division,statement $(2)$ is also correct.
Statement $(3)$ is incorrect because these processes are not exclusive in unicellular organisms; they are exclusive only in multicellular organisms.

(A) Non-living objects exhibit a characteristic type of growth known as extrinsic growth,where the object increases in size due to the accumulation of material on its external surface.
In contrast,living organisms exhibit intrinsic growth,which means they grow from within due to cell division and metabolic activities.
Therefore,statement $(1)$ is the only correct description for non-living objects.

(D) Increase in mass and increase in number of individuals are twin characteristics of growth.
Growth is defined as an increase in size and mass during the development of an organism over a period of time.
It is measured as an increase in biomass and is associated with cell division by mitosis,subsequent increases in cell size,and the differentiation of cells to perform particular functions.

(C) Growth is defined as an increase in mass and an increase in the number of individuals.
In plants,growth by cell division occurs continuously throughout their life span.
In animals,this growth is seen only up to a certain age.
However,cell division occurs in certain tissues to replace lost cells.
Therefore,statement $C$ is incorrect because continuous growth by cell division throughout the life span is a characteristic of plants,not animals.

(B) According to the biological species concept,two organisms belong to the same species if they can interbreed freely under natural conditions to produce fertile offspring. In the case of plants,this means they can cross-pollinate and produce viable seeds that can grow into new,fertile plants. Mere similarity in appearance,chromosome number,or genetic makeup does not guarantee that two organisms belong to the same species.

(B) The replication of genetic information is the most fundamental feature of all living systems.
It ensures the transfer of genetic information from one generation to the next.
This process is essential for the perpetuation of life and allows organisms to create copies of themselves,which is necessary for the continuation of their species.

(C) Defining features are those characteristics that are present in all living organisms without any exception.
$1$. Cellular organization is a defining feature because all living organisms are made up of one or more cells.
$2$. Consciousness (the ability to sense the environment and respond to stimuli) is also a defining property of all living organisms,as even the simplest prokaryotes can sense and respond to environmental cues.
$3$. Growth and reproduction are not considered defining features because non-living objects can also grow (by accumulation of material) and some living organisms (like sterile worker bees or infertile human couples) do not reproduce.

(B) In unicellular organisms,growth and reproduction are inclusive events because they grow by cell division,which simultaneously increases their population size.
Statement $(i)$ is true because an increase in cell number is considered both growth and reproduction in unicellular organisms.
Statement $(ii)$ is true because unicellular organisms increase their mass and size through cell division.
Statement $(iii)$ is false because growth and reproduction are mutually exclusive events only in higher multicellular organisms,not in unicellular organisms.
Therefore,statements $(i)$ and $(ii)$ are correct.

(C) Growth and reproduction are mutually exclusive events in the majority of higher animals and plants.
Growth is defined as an increase in mass and an increase in the number of individuals.
Reproduction is the biological process by which an organism produces offspring similar to itself.
In higher organisms,growth and reproduction are distinct and mutually exclusive processes,meaning they do not occur simultaneously as they do in many unicellular organisms.

(A) Non-living objects exhibit a characteristic type of growth known as extrinsic growth,where the object increases in size due to the accumulation of material on its external surface.
In contrast,living organisms exhibit intrinsic growth,which means they grow from within due to cell division and metabolic processes.
Therefore,statement $(i)$ is the only correct description of growth in non-living objects.

(B) Reproduction is a biological process by which an organism gives rise to young ones (offspring) similar to itself.
It ensures the continuity of the species, generation after generation.
Genetic variations are created and inherited during reproduction.
"$Like\; begets\; like$" is the phrase used to explain the similarity between parents and offspring.

(D) The fundamental characteristics of living organisms include: cellular organization,metabolism,growth,reproduction,consciousness (responsiveness to the environment),and homeostasis.
$A$,$B$,and $C$ are essential defining features or processes observed in living systems.
$D$ (Differentiation from cells to tissues) is a developmental process occurring in multicellular organisms,but it is not considered a universal 'characteristic of life' in the same fundamental sense as metabolism or reproduction,as many living organisms (e.g.,unicellular organisms) do not undergo tissue differentiation.

(C) Growth is defined as an increase in mass and an increase in the number of individuals.
In living organisms,growth occurs from the inside.
However,non-living objects also grow if we take an increase in body mass as a criterion for growth (e.g.,mountains,boulders,and sand mounds grow by accumulation of material on the surface).
Therefore,growth cannot be taken as a defining property of living organisms.
Regarding the options provided:
$1$. Growth is not exclusive to living organisms (non-living things also grow externally).
$2$. Plants grow continuously throughout their life span,whereas animals grow only up to a certain age.
$3$. Growth in living organisms is from inside.
Since statement $C$ is the only scientifically accurate statement among the choices,and the question asks for correct statements,we must evaluate the options carefully. Given the standard context of this question,$C$ is the correct biological fact.

(D) Growth in living organisms is intrinsic,meaning it occurs from within. This is primarily achieved through the division of cells,which leads to an increase in the number of cells and,consequently,an increase in biomass. Accumulation of material by an external agency (like the growth of a mountain or a crystal) is extrinsic and is not a characteristic feature of living organisms.

(D) Growth is defined as an irreversible increase in mass and an increase in the number of individuals.
These two features are collectively referred to as the twin characteristics of growth in living organisms.
Therefore,$(i)$ and $(iii)$ represent the correct twin characteristics.

(B) Metabolism is defined as the sum total of all the chemical reactions occurring in a living organism.
Statement $(i)$ is incorrect because metabolism involves chemical reactions,not just physical reactions.
Statement $(ii)$ is correct because all living organisms,including plants,animals,fungi,and microbes,exhibit metabolism.
Statement $(iii)$ is incorrect because isolated metabolic reactions in-vitro are not living things,although they are considered living reactions.

(D) All the given statements are correct.
$(i)$ All living organisms possess the ability to sense their surroundings and respond to environmental stimuli,which can be physical,chemical,or biological.
$(ii)$ Plants exhibit responses to various external factors such as light,water,temperature,other organisms,and pollutants.
$(iii)$ Photoperiodism is the physiological reaction of organisms to the length of night or a dark period. It significantly affects the process of reproduction in seasonal breeders,including both plants and animals.
$(iv)$ Self-consciousness is the ability to be aware of oneself. Among all living organisms,only human beings possess this unique characteristic.

(C) Growth is defined as an irreversible increase in mass or size of an organism.
In animals,growth is observed only up to a certain age.
However,in plants,growth by cell division occurs continuously throughout their life span.
Therefore,the statement that growth by cell division occurs continuously throughout the life span in animals is incorrect.

(B) Reproduction is not a defining characteristic of living organisms because it is absent in sterile organisms such as mules,hinnies,sterile human couples,and worker bees. Therefore,the statement that reproduction is a characteristic of all living organisms is incorrect.

(D) Metabolism is the sum total of all chemical reactions occurring in a living organism.
It is a defining feature of all living organisms because no non-living object shows metabolism.
While metabolic reactions can be demonstrated $in-vitro$ (outside the body in a cell-free system), these reactions are not 'living things' themselves, but they are 'living reactions'.
Therefore, the statement 'It is not a defining feature of life forms' is incorrect.