Class 10 Science Chapter 7 MCQ

Here, all the statements are correct. Hence, your answer will be option [D].

The disease which are spread by sexual contact with an infected person are called Sexually Transmitted Disease or STD. Example: Gonorrhea, Syphilis and AIDS. Hepatitis is a waterborne a viral disease which affects liver.

In binary fission the parent organism divides to form two new organisms.

Development of placenta and secretion of estrogen are related to female reproductive system. Hence, are not the function of testis at puberty.

Formation of germ cell or sperms take place in the testes and it lies in the scrotum. In the scrotum outside the abdominal cavity, the temperature is about 3 degree Celsius lower than the temperature of the body. Testes lies in the scrotum because the sperm formation require a lower temperature than the normal body temperature.

Regeneration is not exactly the same as the reproduction because most simple animals would not depend on being cut into pieces to be able to reproduce. The regeneration of an organism from its cut body parts occurs by the process of growth and development.

It is “not” necessary to plant the whole potato tuber in the ground to produce the new potato plants. We can even plant, to “cut pieces” of a potato tuber in the ground to obtain new plants potato plants. But all these cut pieces of potato tuber should have a bud or eye on them. Each potato plant produces more than one tuber and each tuber has more than one bud which produce more than one new plant. Due to this, the vegetative propagation method of producing potato plants by tuber is much faster than the production of potato plants from seeds.

Reproduction is not essential for the survival of an individual, but it is an important function of a living being as it helps and organisms to perpetuate it its own kind. Through this process, new individuals are produced, that grow and reproduce again, so as to continue the species generation after generation. Reproduction is a process to maintain the progeny of an organisms.

The new plants produced by artificial vegetative propagation will be exactly like the parent plants. Any desirable features of the parent plant will be replicated in the new plants.

Sexual reproduction occurs between two parents of the same species, not a different species. Sexual reproduction, the offspring are not identical to the parents or to one another. This is because the offspring receive some genes from mother and some from father. Because of mixing of genes on re-establishment of number of chromosome in various different combinations the offspring show both similarities and variations with characters of parents. Thus, creates new combination of variants and each combination is novel.

The flowers are unisexual (papaya, watermelon) contains either stamens or carpels. Since only one reproductive organ is present in them. They depend on cross pollination to form zygote after fertilization. Both stamen and carpels are required for fertilization, so only one of them cannot produce fruits.

The replication or copying of DNA in the cells is done by certain biochemical reaction which synthesize more of genetic material. When the DNA already present in the nucleus of the parent cell is replicated or copied by making more DNA at the time of “asexual reproduction”, then slight variation come in the two copies formed. Due to this, the two DNA molecules formed by replication will be similar but may not be exactly identical to the original DNA. No biochemical reaction can produce 100% same results.

Flowers are the sexual reproductive organs of a plant. They are produced in angiosperms. Majority of flowers are bisexual. After fertilization, they give rise to fruits.

Here, all the statements are correct. Hence, your answer will be option [D].

In sexual reproduction, though the genetic material DNA from two gametes, male and female gametes, combined together to form a new cell “zygote” but the amount of DNA in zygote does not get the doubled. This can be explained as: When a male gamete combined with the female gamete during sexual reproduction, then the new cell zygote will have the normal amount of DNA or normal number of chromosomes in it. For example, the human sperm has 23 chromosomes and the human egg or ovum has also 23 chromosomes. So, when a sperm and an egg fuse together during fertilization, then the zygote formed will have 23 + 23 = 46 chromosomes, which is the normal number of chromosomes.

Under favorable condition (like damp and warm conditions, nutrients), the airborne spores land on food, germinate and produce new plants. These spores spread into air when spore case of plant containing hundreds of spore busts.

The first occurrence of menstruation at puberty is called menarche. And the permanent stoppage of menstruation in a woman is called menopause. Menopause occurs in women at the age of about 45 to 50 years.

In vegetative propagation, vegetative parts of a plant such as root, stem leaf, etc. can produce new plants. Vegetative reproduction is seen in plants like orchids, ornamental plants, grasses, banana, rose, jasmine etc.

Here, all the statements are correct. Hence, your answer will be option [D].

The number of chromosomes in parents and off-springs of a particular species remains constant due to halving of chromosome during gamete formation. The gametes are a special type of cells which contain only half of the amount of DNA as compared to normal cells of an organism. So when a male gamete combines with a female gamete during sexual reproduction, then the new cell “zygote” will have normal amount of DNA.

Correct sequence of reproductive stages in flowering plants is → formation of gametes → fusion of gametes to form zygote → zygote develops into embryo in the ovary → ovule develops a tough coat and converts into a seed.

In Spirogyra, asexual reproduction take place by fragmentation, i.e. organisms simply breaks up into smaller pieces upon maturation. Each pieces is grow into new individuals without forming any gametes.

Characters are transmitted from parents to offspring through genes. Genes are the hereditary units of the body in living organisms. Chromosomes in the nucleus of a cell contain information for the inheritance of features from parents in the form of DNA (Deoxyribonucleic acid). This DNA contains genes.

Offspring have greater similarity as only one parent is involved in a sexual reproduction thus no garments one former. The basis of asexual reproduction is mitosis (division of a nucleus into two identical daughter nuclei). Each daughter nucleus has same genetic makeup because of replication of parental DNA. The new offspring produced are called clones.

The correct sequence of events are: Pollination (transfer of pollen from stamen to stigma) → Fertilization (fusion of germ cells to form zygote) → Embryo formation (zygote divides several times to form an embryo within the ovule) → Seedling (ovule develops a tough coat and converts into a seed).