What is living? Questions in English

(D) According to the biological species concept,a species is defined as a group of organisms that can interbreed under natural conditions to produce fertile offspring.
Therefore,two plants belong to the same species if they can freely interbreed and produce viable,fertile seeds.

(A) The definition of a living organism includes several key characteristics such as growth,reproduction,metabolism,cellular organization,and consciousness. While growth and reproduction are fundamental,they are not defining features that apply to every single individual (e.g.,sterile worker bees or mules do not reproduce). However,in the context of general biological principles,the most comprehensive statement describing the life cycle and potential of living organisms is that they grow,develop,and reproduce. Option $A$ is the most standard description of these biological processes.

(A) Statement $P$ is correct because reproduction,growth,development,adaptation,and death are fundamental biological processes that characterize living organisms.
Statement $Q$ is also correct because all living organisms require energy to maintain their metabolic activities,which involves the transformation of energy (e.g.,from chemical energy in food to $ATP$).
However,Statement $Q$ is not the direct cause or explanation for the specific list of characteristics mentioned in Statement $P$. These are distinct biological attributes. Therefore,both statements are correct,but $Q$ does not explain $P$.

(D) Statement $I$ is correct: Heredity involves the transmission of $DNA$ from parents to offspring.
Statement $II$ is correct: Adaptation is a fundamental characteristic where organisms adjust to their environment.
Statement $III$ is incorrect: Metabolism,which involves complex energy transformations,is a defining feature of all living organisms and is absolutely essential for life.
Statement $IV$ is correct: Morphogenesis is the biological process that causes an organism to develop its shape during growth and development.
Therefore,statements $I, II,$ and $IV$ are correct.

(C) $1$. Living organisms exhibit a unique property called 'consciousness' or the ability to sense and respond to environmental stimuli.
$2$. This is considered a defining characteristic because it is present in all living organisms without exception.
$3$. Isolated metabolic reactions in vitro (Option $A$) are living reactions but not living organisms themselves.
$4$. Increase in mass (growth) occurs in non-living objects as well (e.g.,mountains,boulders) due to external accumulation (Option $D$),and internal growth is not exclusive to all living forms in the same manner as consciousness.

(C) living organism is a self-replicating,evolving,and self-regulating interactive system capable of responding to external stimuli. While physics and chemistry provide the basis for understanding the molecular mechanisms,the true understanding of a living organism comes from studying the characteristics related to its biological functions,such as metabolism,growth,reproduction,and consciousness. Therefore,option $C$ is the most appropriate answer.

(D) Reproduction is a characteristic feature of living organisms,but it is not an all-inclusive defining characteristic of life. Sterile organisms,such as mules,worker bees,or infertile human couples,cannot reproduce. Therefore,they are unable to produce new organisms at maturity. This confirms that reproduction is not an essential feature for defining a living organism.

(C) The study of non-living matter,including its structure,composition,and properties,is primarily covered under the physical sciences,which include $Physics$ and $Chemistry$. Physics deals with the fundamental laws of nature and energy,while Chemistry focuses on the composition and reactions of substances. Therefore,both $Physics$ and $Chemistry$ are used to understand non-living components.

(D) The defining characteristics of living organisms are those features that are present in all living beings without exception.
$1$. Growth and development are observed in all living organisms,although they are not exclusive (as non-living objects can also grow by accumulation).
$2$. Consciousness of the environment (self-consciousness/response to stimuli) is a defining property because it is present in all living organisms and is not found in non-living objects.
$3$. Adaptation is a fundamental trait of life.
Since all these features are essential attributes of life,the correct answer is $D$.

(B) The fundamental characteristic property that distinguishes living organisms from non-living matter is the 'presence of life'. While living organisms may have specific shapes,this is not a universal defining property as some organisms (like Amoeba) have irregular shapes. Therefore,the presence of life is the primary defining characteristic.

(D) The definition of a living organism is based on its functional characteristics such as growth,reproduction,metabolism,cellular organization,and consciousness. While 'having life' is a general concept,it is defined by these specific functional attributes. Therefore,both the presence of life and the functional characteristics are considered in defining a living organism. Hence,the correct option is $D$.

(D) Living organisms exhibit several defining characteristics that distinguish them from non-living matter.
$1$. Growth and development: All living organisms grow in mass and number of cells.
$2$. Reproduction: Living organisms produce offspring similar to themselves to ensure the continuity of the species.
$3$. Consciousness: The ability to sense their environment and respond to external stimuli is a defining property of all living organisms.
Since all these features are characteristic of life,the correct option is $(D)$.

(D) living organism is defined by its ability to perform essential biological processes such as metabolism,growth,reproduction,and response to stimuli. These processes allow the organism to maintain homeostasis and interact effectively with its environment. Therefore,both possessing life and the ability to perform these functions are characteristics of a living organism.

(C) The characteristics of living organisms follow a biological progression throughout their life cycle.
$1$. Growth and Development are the initial phases of an organism's life.
$2$. Reproduction is a key feature that ensures the continuity of the species.
$3$. Metabolism is the sum total of all chemical reactions occurring within the body,which is essential for maintaining life.
$4$. Response to environment (consciousness) allows organisms to sense and react to external stimuli.
$5$. Adaptation refers to the evolutionary process where an organism becomes better suited to its habitat.
$6$. Senescence (aging) and eventually Death are the final stages of the biological life cycle.
Option $(C)$ correctly represents this logical sequence of biological processes.

(D) Reproduction is a characteristic feature of living organisms. Both unicellular and multicellular organisms are capable of reproduction to produce offspring. Sterile organisms (like worker bees or mules) are living organisms that cannot reproduce,but the question asks which types of organisms generally possess the capability of reproduction. Therefore,both unicellular and multicellular organisms exhibit the ability to reproduce.

(B) In living organisms, growth is a characteristic feature.
In plants, growth by cell division occurs continuously throughout their lifespan.
However, in animals, growth is observed only up to a certain age, after which the organism stops growing in size and focuses on maintenance and repair.
Therefore, the correct answer is $Animals$.

(D) Living organisms possess the ability to sense their environment and respond to environmental stimuli.
These stimuli can be physical,chemical,or biological.
$1$. Physical factors: Light,temperature,and water are essential abiotic factors that influence the metabolic activities and behavior of organisms.
$2$. Chemical factors: Pollutants and other chemical substances in the environment can trigger physiological responses.
$3$. Biological factors: Interactions with other organisms (predation,competition,symbiosis) also elicit responses.
Therefore,living organisms respond to all these external factors.

(D) Living organisms exhibit the property of consciousness or irritability,which is the ability to sense their environment and respond to environmental stimuli such as light,water,temperature,pollutants,or other organisms. This response to environmental factors is a defining characteristic of living beings. Among the given options,while growth and reproduction are biological processes,the specific interaction and response to external environmental factors is best categorized under the broader scope of physiological and developmental responses,often linked to morphogenesis or general irritability. However,in the context of $NCERT$,'consciousness' is the defining feature. Given the options,'Morphogenesis' (the biological process that causes an organism to develop its shape) is highly influenced by environmental factors.

(A) In biological systems,the properties of tissues are not present in the constituent cells but arise as a result of interactions among the constituent cells. 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. These interactions result in emergent properties at a higher level of organization. Therefore,in higher organisms,the unique phenomena of life are the result of interactions among the constituent parts of the body.

(C) The properties of tissues are not present in the constituent cells but arise as a result of interactions among the constituent cells. 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. These interactions result in emergent properties at a higher level of organization.

(C) The study of living organisms,including their classification,characteristics,and species,is collectively known as $Biology$.
$Cytology$ is the study of cells.
$Biochemistry$ is the study of chemical processes within and relating to living organisms.
$Physics$ deals with matter and energy.
Therefore,the study of species is a fundamental aspect of $Biology$.

(C) Biological organization ranges from the sub-microscopic level to the biosphere.
$1$. Atoms,molecules,and organelles are considered non-living components because they do not exhibit the fundamental characteristics of life (such as metabolism,reproduction,or cellular organization) on their own.
$2$. $A$ cell is the basic structural and functional unit of life,making it the first level of biological organization.
$3$. $A$ society is a group of living organisms interacting with each other.
$4$. Among the given options,an atom is the most fundamental non-living level of organization.

(A) The levels of biological organization are studied in different scientific fields:
$1$. $(a)$ Tissues are studied under $(iv)$ Cell Biology (or Histology).
$2$. $(b)$ Atoms are the fundamental units studied in $(iii)$ Physics and Chemistry.
$3$. $(c)$ Species are studied in the context of $(i)$ Ecology (interaction of organisms with their environment).
$4$. $(d)$ Organisms are the primary focus of $(ii)$ Biology.
Therefore,the correct matching is $a-iv, b-iii, c-i, d-ii$.

(D) The levels of biological organization are categorized based on their scale and visibility:
$1$. $(a)$ Visible: Organisms are visible to the naked eye,so $(a)$ matches $(ii)$.
$2$. $(b)$ Microscopic: Cells are visible under a microscope,so $(b)$ matches $(i)$.
$3$. $(c)$ Sub-microscopic: Molecules are too small to be seen with a standard light microscope,so $(c)$ matches $(iv)$.
$4$. $(d)$ Conceptual: $A$ community is an abstract ecological concept representing interacting populations,so $(d)$ matches $(iii)$.
Therefore,the correct matching is $a-ii, b-i, c-iv, d-iii$.

(B) To solve this,we analyze the scale of organization:
$1$. Macroscopic scale $(a)$ involves complex structures like Organ systems $(R)$,which are studied under Biology $(iv)$. Thus,$a-R-iv$.
$2$. Sub-microscopic scale $(b)$ involves Sub-atomic particles $(S)$,which are studied under Physics $(i)$. Thus,$b-S-i$.
$3$. Conceptual scale $(c)$ involves large-scale interactions like Ecosystems $(P)$,which are studied under Ecology $(ii)$. Thus,$c-P-ii$.
$4$. Microscopic scale $(d)$ involves cellular structures like Tissues $(Q)$,which are studied under Cell Biology $(iii)$. Thus,$d-Q-iii$.
Therefore,the correct matching is $a-R-iv, b-S-i, c-P-ii, d-Q-iii$.

(A) In the hierarchy of biological organization,levels are categorized based on their scale and visibility.
$A$. Molecules are submicroscopic,meaning they cannot be seen even with a standard light microscope.
$B$. Atoms are also submicroscopic,not visible to the naked eye.
$C$. Organs are macroscopic (visible to the naked eye),not microscopic.
$D$. Organelles are microscopic structures found within cells,not conceptual.
Therefore,the correct pair is $A$.

(D) The correct matching is as follows:
$(a)$ Macroscopic scale refers to the level of (ii) Organisms.
$(b)$ Microscopic scale refers to the level of $(i)$ Cells.
$(c)$ Sub-microscopic scale refers to the level of (iv) Atoms.
$(d)$ Conceptual scale refers to the level of (iii) Society.
Therefore,the correct sequence is $(a)$-(ii),$(b)$-$(i)$,$(c)$-(iv),$(d)$-(iii).

(C) Classification is the process by which anything is grouped into convenient categories based on some easily observable characters.
$1$. It involves grouping organisms into meaningful categories (taxa).
$2$. It provides a convenient taxonomic arrangement for study.
$3$. It is based on easily observable characteristics.
$4$. Nomenclature (naming of organisms) is a separate process from classification,although they are both part of taxonomy. Therefore,nomenclature is not a step or definition of classification itself.

(A) Identification is the process of correctly describing an organism and assigning it a specific name,which allows for its meaningful representation and distinction from other organisms.
Classification is the process of grouping organisms into categories based on observable characters.
Therefore,the process that provides a specific,meaningful representation is Identification.

(D) Diversity in living organisms is observed at various levels. Every organism exhibits specific structural characteristics,performs distinct physiological functions,and displays unique behavioral patterns in response to its environment. Therefore,the fundamental types of diversity observed in living organisms are structure,behavior,and function.

(C) The correct answer is $C$.
$1$. Isolated metabolic reactions occurring in vitro are not living things themselves,but they are living reactions.
$2$. Increase in mass is observed in both living and non-living objects (e.g.,mountains,boulders,and sand mounds grow by accumulation of material on the surface).
$3$. Consciousness,which is the ability to sense the environment and respond to environmental stimuli,is the defining property of living organisms. Humans are the only organisms aware of themselves,i.e.,they have self-consciousness and memory of events.

(D) The correct answer is $D$. Responsiveness to touch (or consciousness) is considered a defining property of living organisms.
$1$. Consciousness is the ability of organisms to sense their environment and respond to environmental stimuli,which could be physical,chemical,or biological.
$2$. All organisms,from the prokaryotes to the most complex eukaryotes,can sense and respond to environmental cues.
$3$. While growth and reproduction are characteristics of living organisms,they are not 'defining' features because non-living things can also grow (e.g.,crystal growth) and some living organisms (like sterile worker bees or infertile human couples) do not reproduce.
$4$. Therefore,consciousness is the only feature that is present in all living organisms without exception.

(D) The correct answer is $(D)$.
According to the biological species concept,organisms are classified as belonging to the same species if they can interbreed freely under natural conditions to produce fertile offspring.
In the case of plants,if two individuals can reproduce freely with each other and form viable seeds,they are considered to belong to the same species.
While genetic similarity,morphological appearance,and chromosome numbers are important,the ability to interbreed is the definitive criterion for species classification.

(D) All living organisms are made up of cells. The fundamental characteristics of living cells include growth,reproduction,metabolism,and development. Since all the options listed represent essential biological processes that occur within or as a result of cellular activity,the correct answer is $D$.

(A) Growth is defined as an irreversible increase in the size,volume,or mass of an organism or its parts. In biological terms,an increase in body mass and an increase in the number of individuals are twin characteristics of growth. Therefore,an increase in body mass is considered as growth.

(D) The characteristics of living organisms include growth,reproduction,metabolism,consciousness,and cellular organization.
$A$,$B$,and $C$ are defining features or characteristics of living organisms.
$D$ (Light) is an abiotic environmental factor,not a characteristic of living organisms.
Therefore,$D$ is the odd one out.

(A) Growth is defined as an irreversible increase in the mass and number of cells or individuals.
In multicellular organisms,growth refers to an increase in mass and an increase in the number of individuals (or cells).
These two features,i.e.,increase in mass and increase in number of individuals,are known as the 'twin characteristics' of growth.
Therefore,$X$ is mass,$Y$ is number,and $Z$ is twin.

(D) The ability to sense the environment and respond to environmental stimuli is a defining property of living organisms.
$1.$ This statement is incorrect because sensing the environment is not a characteristic of non-living things.
$2.$ This statement is correct as consciousness (sensing and responding to stimuli) is a fundamental feature of all living organisms.
$3.$ This statement is incorrect because stimuli can indeed be physical,chemical,or biological in nature.
Therefore,only statement $2$ is correct.

(A) Metabolism is the sum total of all chemical reactions occurring in a living organism.
Statement $X$ is correct because metabolism is a defining feature of all living organisms,and non-living objects do not show metabolic activities.
Statement $Y$ is also correct because metabolic reactions can be performed in vitro (outside the body in a cell-free system). Such reactions are considered living reactions,although the system itself is not a living organism.
Therefore,both statements are correct.

(B) In unicellular organisms like bacteria and algae,growth and reproduction are synonymous because they increase in cell number to reproduce.
In plants,growth occurs continuously throughout their life span due to the presence of meristematic tissues.
In animals,growth is observed only up to a certain age,after which they stop growing.
Multicellular organisms grow by cell division.
Therefore,the statement 'In plants,growth is seen only up to a certain age' is false,as plants exhibit indeterminate growth.

(D) Living organisms are defined by several key characteristics that distinguish them from non-living matter.
$1$. Self-replicating: Living organisms have the ability to reproduce and create copies of themselves.
$2$. Self-regulating: They maintain homeostasis,which is the ability to regulate their internal environment despite external changes.
$3$. Evolving: Living organisms possess the capacity to adapt and evolve over generations through natural selection.
Since all these properties are fundamental characteristics used to define life,the correct answer is $D$.

(D) In unicellular organisms such as $Amoeba$,$Chlamydomonas$ (unicellular algae),and $Bacteria$,reproduction is synonymous with growth.
This is because these organisms increase in cell number through cell division,which is the definition of both growth (increase in number of individuals) and reproduction (production of progeny).
Therefore,for these organisms,growth and reproduction are mutually inclusive events.

(C) Statement $X$ is correct because non-living objects like mountains,boulders,and sand mounds exhibit growth by the accumulation of material on their surface (extrinsic growth).
Statement $Y$ is incorrect because growth is not a characteristic of only non-living things; it is also a characteristic of living organisms (intrinsic growth).
Therefore,$X$ is correct and $Y$ is incorrect.

(C) $1$. Reproduction is not a defining characteristic of all living organisms because some organisms like mules,worker bees,and infertile human couples do not reproduce.
$2$. Metabolism is a defining feature of all living organisms; it occurs in every living cell.
$3$. In unicellular organisms like $Amoeba$,growth and reproduction are synonymous as they increase in cell number through cell division.
$4$. Growth is not a defining property of living organisms because non-living objects like mountains,boulders,and sand mounds also grow by accumulation of material on the surface.

(C) Statement $(i)$ is correct because growth is a defining characteristic of living organisms,where they increase in mass and number of cells.
Statement $(ii)$ is incorrect because not all organisms reproduce; for example,sterile worker bees,mules,and infertile human couples do not reproduce.
Statement $(iii)$ is correct because unicellular organisms like Amoeba reproduce through cell division (binary fission),which is synonymous with growth in these organisms.
Therefore,statements $(i)$ and $(iii)$ are correct.

(C) Reproduction is a characteristic feature of living organisms,but it is not an all-inclusive defining characteristic of life.
Some living organisms,such as mules,worker bees,and infertile human couples,do not reproduce.
Therefore,the inability to reproduce does not make them non-living.
Thus,the correct statement is that both mules and worker bees cannot reproduce.

(A) The process of classification involves several steps,including characterization,identification,nomenclature,and classification.
Identification is the first and fundamental step in the process of taxonomy,where an organism is correctly recognized and assigned to a known group based on its characteristics.
Without proper identification,it is impossible to proceed with naming (nomenclature) or grouping (classification) the organism.

(C) Living organisms exhibit several characteristics such as growth,reproduction,metabolism,and consciousness.
$1$. Isolated metabolic reactions in vitro are not living things but surely living reactions.
$2$. Non-living objects can also grow if we take growth as an increase in mass (e.g.,mountains,boulders,and sand mounds grow by accumulation of material on the surface).
$3$. Living organisms grow from the inside,which is a defining feature.
$4$. Consciousness or the ability to sense the environment and respond to stimuli is the most technically complicated and exclusive characteristic of all living organisms.

(B) The most fundamental and essential characteristic of all living systems is the ability to store and pass on genetic information through self-replication. This process ensures the continuity of life and the transmission of hereditary traits from one generation to the next. While metabolic activities and energy usage are vital,self-replication is the defining feature that distinguishes living organisms from non-living matter at the molecular level.

(D) Living organisms exhibit several characteristics such as growth,reproduction,metabolism,cellular organization,and consciousness.
Among these,consciousness (the ability to sense their environment and respond to environmental stimuli) is considered the defining property of living organisms.
While growth and reproduction are characteristics of living beings,they are not 'defining' properties because non-living objects can also grow (e.g.,mountains,boulders) and some living organisms (e.g.,sterile worker bees,infertile human couples) cannot reproduce.
Therefore,the ability to sense the environment and respond to stimuli is the most distinct feature that separates living from non-living things.