Mix Examples - How do Organisms Reproduce? Questions in English

(D) Binary fission is a form of asexual reproduction where a single parent cell divides into two equal daughter cells.
$Amoeba$ is a unicellular organism that reproduces through binary fission.
In this process, the nucleus divides first, followed by the division of the cytoplasm.
$Planaria$ reproduces through regeneration.
$Earthworm$ reproduces sexually.
$Hydra$ reproduces primarily through budding.

(B) $Spirogyra$ is a filamentous green alga. When it matures, its body breaks into smaller pieces or fragments. Each of these fragments grows into a new individual. This process of asexual reproduction is known as $Fragmentation$.

(A) Vegetative reproduction is a form of asexual reproduction in plants where new individuals are formed from vegetative parts like roots,stems,or leaves.
In $Potato$ ($Solanum$ $tuberosum$),the stem is modified into a tuber. The 'eyes' on the potato tuber are axillary buds that can sprout to form new plants.
$Sweet$ $potato$ reproduces through adventitious roots.
$Bryophyllum$ reproduces through foliar buds (leaves).
$Oscillatoriaceae$ is a family of cyanobacteria that reproduces through fragmentation.
Therefore,the correct answer is $Potato$.

(D) Vegetative propagation is a type of asexual reproduction in plants where new individuals are formed from vegetative parts like roots,stems,or leaves.
In $Bryophyllum$ (commonly known as the sprout leaf plant),small adventitious buds develop along the notches of the leaf margins.
When these buds fall on moist soil,they develop into new independent plants.
Therefore,$Bryophyllum$ is the correct example of vegetative propagation through leaves.

(C) Vegetative propagation is a form of asexual reproduction in plants.
In $Potato$ ($Solanum$ $tuberosum$), the stem is modified into a tuber.
The tuber has 'eyes' which are axillary buds.
These buds grow into new plants when placed in the soil, making it an example of vegetative propagation through the stem.
$Bryophyllum$ propagates through leaves, while $Sweet$ $potato$ and $Radish$ propagate through roots.

(A) Vegetative propagation is a type of asexual reproduction in plants.
Artificial methods of vegetative propagation are techniques developed by humans to multiply plants.
Examples include cutting,layering,and grafting.
Fragmentation,budding,and spore formation are natural methods of asexual reproduction found in various organisms.

(D) Grafting is a technique used in horticulture where tissues from one plant are inserted into those of another so that the two sets of vascular tissues may join together.
Since this method is performed by humans to propagate plants artificially,it is classified as a type of artificial vegetative propagation.
Therefore,the correct option is $D$.

(A) Grafting is an artificial vegetative propagation method used in plants.
In this process,two different plant parts are joined together.
The part of the plant that provides the root system is known as the $Stock$.
The part that is grafted onto the stock,which provides the shoot system,is known as the $Scion$.
Therefore,the correct answer is $Stock$.

(B) Grafting is an artificial vegetative propagation method.
In this process,two plant parts are joined together.
The plant that provides the root system is called the $Stock$.
The part of the plant that is attached to the $Stock$ (the upper part) is called the $Scion$.
Therefore,the part attached to the cut stem is the $Scion$.

(C) Grafting is a horticultural technique whereby tissues of plants are joined so as to continue their growth together.
In this method,the upper part of one plant (scion) is joined to the root system of another plant (stock).
This allows the grower to combine the desirable traits of two different plants,such as the high-quality fruit of one variety and the strong,disease-resistant root system of another.

(C) Grafting is a horticultural technique whereby tissues of plants are joined so as to continue their growth together. In this method,a high-quality variety (scion) is joined to a common or wild variety (stock) that has a strong root system. This allows the resulting plant to produce high-quality fruits while benefiting from the hardiness of the rootstock. Therefore,grafting is the correct method for obtaining high-quality mangoes from a common mango tree.

(D) Artificial vegetative propagation refers to human-assisted methods of plant reproduction.
$A$,$B$,and $C$ (Cutting,Grafting,and Layering) are standard techniques used by humans to propagate plants artificially.
$D$ (Budding) is a type of asexual reproduction found in organisms like $Hydra$ and yeast,which is a natural process,not an artificial vegetative propagation method.

(A) Layering is a method of vegetative propagation where a branch of the plant is bent towards the ground and covered with soil.
After some time,adventitious roots develop from the part of the stem buried in the soil.
Once the roots are established,this branch is detached from the parent plant to grow as an independent plant.
This technique is commonly used in plants like jasmine and strawberry.

(C) The process of fusion of a male gamete $(n)$ and a female gamete $(n)$ is known as fertilization. This fusion results in the formation of a single-celled diploid structure called a zygote $(2n)$. The zygote is the first cell of a new organism.

(B) Genetic variation occurs in sexual reproduction because it involves the fusion of two different gametes (male and female) from two parents.
During the process of meiosis,genetic recombination (crossing over) takes place,which leads to new combinations of genes in the offspring.
In contrast,asexual reproduction,vegetative propagation,and budding are methods where a single parent produces offspring that are genetically identical to the parent (clones).

(D) In sexually reproducing organisms,normal body cells (somatic cells) are diploid $(2n)$,meaning they contain two sets of chromosomes. Germ cells (gametes) are produced through the process of meiosis,which reduces the chromosome number by half. Therefore,germ cells are haploid $(n)$,containing exactly half the number of chromosomes found in normal body cells. This ensures that when fertilization occurs,the resulting zygote restores the original diploid number $(2n)$.

(A) Human somatic cells are diploid $(2n)$,containing $46$ chromosomes.
During the process of meiosis,which occurs during gametogenesis,the chromosome number is reduced to half.
Therefore,human gametes (sperm and egg cells) are haploid $(n)$ and contain $23$ chromosomes each.
Thus,a human sperm cell contains $23$ chromosomes.

(C) human somatic cell (body cell) is diploid $(2n)$,meaning it contains two sets of chromosomes.
In humans,the haploid number $(n)$ is $23$,which is found in gametes (sperm and egg cells).
Therefore,the diploid number $(2n)$ in a somatic cell is $2 \times 23 = 46$ chromosomes.
Thus,the correct answer is $46$.

(D) In angiosperms (flowering plants),the flower is the specialized reproductive structure.
It contains the male reproductive parts (stamen) and the female reproductive parts (pistil/carpel).
These organs are responsible for sexual reproduction,leading to the formation of seeds and fruits.

(B) In the majority of flowering plants,the flowers are bisexual (also known as hermaphrodite).
This means that both the male reproductive part (stamen) and the female reproductive part (pistil/carpel) are present within the same flower.
This arrangement facilitates self-pollination and ensures reproductive success in many species.

(C) In a flower,the female reproductive part is the carpel or pistil.
The carpel consists of three parts: the stigma,the style,and the ovary.
The ovary contains the ovules,and inside each ovule,the female germ cell (egg cell) is present.
Therefore,the female germ cells are located in the ovary.

(A) Puberty is the period during which adolescents reach sexual maturity and become capable of reproduction.
In girls, the onset of puberty typically occurs between the ages of $10$ and $14$ years.
Among the given options, $10$ years is the most appropriate age representing the beginning of this developmental phase.

(B) Puberty is the period during which an adolescent's body becomes sexually mature. In boys,the onset of puberty typically occurs between the ages of $13$ and $14$ years. During this phase,various physiological changes occur,such as the development of secondary sexual characteristics,due to the increased production of testosterone.

(B) The primary sex organ in the male reproductive system is the $Testis$.
It performs two main functions:
$1$. Production of male gametes called $Sperm$ (spermatogenesis).
$2$. Secretion of the male sex hormone called $Testosterone$.
Other organs like the seminal vesicle and prostate gland are accessory reproductive glands.

(D) The testes in males are responsible for the production of the primary male sex hormone,known as $Testosterone$.
This hormone plays a crucial role in the development of male reproductive organs and secondary sexual characteristics during puberty,such as the deepening of the voice,growth of facial hair,and muscle development.
$Estrogen$ and $Progesterone$ are female sex hormones produced by the ovaries,while $Aldosterone$ is a mineralocorticoid hormone produced by the adrenal glands.

(B) The human female ovary is a primary reproductive organ that performs two main functions: the production of the female gamete (ovum) and the secretion of steroid hormones.
These steroid hormones are known as Estrogen and Progesterone.
Estrogen is responsible for the development of secondary sexual characteristics in females,while Progesterone is essential for the maintenance of the uterine lining during pregnancy.
Testosterone is primarily a male sex hormone produced by the testes,and Aldosterone is a mineralocorticoid hormone produced by the adrenal cortex.

(B) In human males,the testes are located outside the abdominal cavity within a pouch-like structure called the scrotum.
This location is essential because the formation of germ cells (sperm) requires a temperature that is $2-2.5^{\circ}C$ lower than the normal body temperature.

(C) The male reproductive system includes primary sex organs (testes) and accessory reproductive glands.
Accessory glands in the male reproductive system include the seminal vesicles,prostate gland,and bulbourethral glands.
These glands secrete fluids that nourish and transport sperm.
Testis is the primary sex organ,ovary is the female primary sex organ,and the pancreas is a digestive gland.

(D) The male reproductive system consists of the testes,vas deferens,seminal vesicles,prostate gland,and penis.
Ovary,Fallopian tube,and Uterus are parts of the female reproductive system.
Therefore,the prostate gland is the correct organ included in the male reproductive system.

(C) The testes are the primary male reproductive organs.
Their two main functions are:
$(1)$ Production of male germ cells (sperm) through spermatogenesis.
$(2)$ Secretion of the male sex hormone,testosterone,which is responsible for secondary sexual characteristics in males.
Therefore,statements $(1)$ and $(4)$ are correct.

(A) The testes are located outside the abdominal cavity in a pouch called the scrotum.
This is because the process of spermatogenesis (sperm production) requires a temperature that is $2^{\circ}C$ to $3^{\circ}C$ lower than the normal internal body temperature.
The scrotum helps in maintaining this lower temperature,which is essential for the viability and proper development of sperm.

(B) In the female reproductive system,there is a pair of ovaries. They are located in the abdominal cavity,one on each side of the lower abdomen. The ovaries are responsible for the production of the female gamete (ovum) and the secretion of female sex hormones like estrogen and progesterone.

(B) In the female reproductive system,the $Ovary$ is the primary reproductive organ.
It performs two main functions:
$1$. Production of female gametes (eggs or ova).
$2$. Secretion of female sex hormones like estrogen and progesterone.
Therefore,the correct option is $B$.

(D) The fallopian tube (oviduct) consists of three parts: the infundibulum,the ampulla,and the isthmus.
$1$. The part closer to the ovary is the funnel-shaped infundibulum.
$2$. The edges of the infundibulum possess finger-like projections called fimbriae,which help in the collection of the ovum after ovulation.
$3$. Therefore,the funnel-shaped structure is known as the infundibulum.

(B) The process of releasing a mature ovum (egg) from the ovary into the fallopian tube is known as $Ovulation$. This is a key event in the female reproductive cycle.

(D) In human females, fertilization is the process where the sperm fuses with the ovum. This event typically occurs in the $Fallopian$ tube (also known as the oviduct). After ovulation, the ovum is released from the ovary and travels into the fallopian tube, where it meets the sperm. The resulting zygote then travels to the uterus for implantation.

(A) In human females,the process of fertilization occurs in the fallopian tube. After fertilization,the resulting zygote undergoes cleavage and develops into an embryo. This embryo then travels to the uterus,where it gets implanted in the uterine wall (endometrium). The uterus is specifically adapted to provide nourishment and protection to the developing embryo throughout the gestation period.

(B) In human females,the menstrual cycle typically lasts for about $28$ days.
However,the actual phase of menstruation (the bleeding phase) typically lasts for $3$ to $5$ days.
During this period,the uterine lining (endometrium) breaks down and is shed through the vagina.

(A) In human females,the process of ovulation occurs once every month.
Typically,only one mature egg (ovum) is released by one of the two ovaries during each menstrual cycle.
This process is regulated by hormones and alternates between the two ovaries.

(C) The $Placenta$ is a specialized tissue that develops between the embryo and the mother's uterine wall.
It facilitates the transfer of nutrients, oxygen, and waste products between the mother's blood and the developing fetus.
The embryo receives nutrition and oxygen from the mother's blood through the $Placenta$ and the umbilical cord.

(B) In human females,the reproductive phase begins at puberty (menarche) and ends at a stage known as menopause.
Menopause is the permanent cessation of the menstrual cycle.
This process typically occurs between the ages of $45$ and $50$ years,marking the end of the reproductive capacity of the female.

(C) The menstrual cycle in human females is a physiological process that occurs periodically.
In a healthy adult female,the average duration of a menstrual cycle is approximately $28$ to $29$ days.
This cycle involves the maturation of an egg (ovum),its release (ovulation),and the preparation of the uterine lining for potential pregnancy.
If fertilization does not occur,the uterine lining is shed,resulting in menstruation.

(C) In human females,the reproductive phase begins at puberty with the onset of menstruation,known as $Menarche$.
As a female approaches the age of $45-50$ years,the ovaries stop releasing eggs and the production of reproductive hormones declines significantly.
This permanent cessation of the menstrual cycle is known as $Menopause$.
Therefore,the correct option is $C$.

(B) condom is a barrier method of contraception that is used by males to prevent pregnancy and the transmission of sexually transmitted infections $(STIs)$.
It acts as a physical barrier that prevents the sperm from reaching the female reproductive tract.
Other options like Loop,Copper-$T$,and Mala-$D$ are methods primarily used by females.

(A) The surgical procedure performed in females to prevent pregnancy by blocking the fallopian tubes is known as $Tubectomy$.
In this procedure,the fallopian tubes are either cut or tied,which prevents the egg from reaching the uterus and thus prevents fertilization.
$Vasectomy$ is the corresponding surgical procedure performed in males.
Therefore,the correct option is $A$.

(C) The bacterium $Treponema$ $pallidum$ is the causative agent of the sexually transmitted disease known as Syphilis.
$AIDS$ is caused by the $Human$ $Immunodeficiency$ $Virus$ $(HIV)$.
$Gonorrhea$ is caused by the bacterium $Neisseria$ $gonorrhoeae$.
$Hepatitis$ is a viral infection primarily affecting the liver.

(B) $Neisseria$ $gonorrhoeae$ is a Gram-negative diplococcus bacterium.
It is the causative agent of the sexually transmitted infection known as Gonorrhoea.
$AIDS$ is caused by the Human Immunodeficiency Virus $(HIV)$.
Syphilis is caused by the bacterium $Treponema$ $pallidum$.
Hepatitis is a viral infection affecting the liver (e.g.,Hepatitis $B$ virus).

(A) Syphilis is a sexually transmitted infection $(STI)$ caused by the bacterium $Treponema$ $pallidum$.
$Treponema$ $pallidum$ is a spirochete bacterium that enters the body through mucous membranes or skin abrasions.
Option $A$ is the correct answer.
$B$ causes gonorrhea, $C$ causes typhoid fever, and $D$ causes cholera.

(A) The disease $AIDS$ (Acquired Immuno Deficiency Syndrome) is caused by the Human Immunodeficiency Virus $(HIV)$.
Gonorrhea and Syphilis are bacterial infections caused by $Neisseria$ $\text{gonorrhoeae}$ and $Treponema$ $\text{pallidum}$ respectively.
Infertility is a condition, not a specific infectious disease caused by a pathogen.
Therefore, the correct option is $A$.

(D) The $NACO$ (National $AIDS$ Control Organization) is the division of the Ministry of Health and Family Welfare in India that provides leadership to the national $AIDS$ control programme. It is responsible for creating awareness about $AIDS$ and providing information related to reproductive health and sexually transmitted diseases.