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.

Sperms formed in testis are delivered through the vas deferens which joins with another tube called urethra, coming from the urinary bladder.

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

Microscopic single celled animal, plasmodium is a protozoa which reproduces by the method of “Multiple fission”.

In early e teenage girls should, breast size increased with darkening of the skin of nipples at the tip of breast. Also, girls begin to menstruate at around this time. In human females, this reflects onset of reproductive phase.

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.

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

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.

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.

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

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

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

The average gestation period in humans or the average duration of human pregnancy is about nine months or about 38 weeks. During the gestation period, the foetus grows to become a baby.

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.

The thread like structure of the bread mould, Rhizopus are called hyphae. The tiny blobs present on them which contains cells or spores are sporangia. The spores eventually develop into new Rhizopus individuals, when they come in the contachment an other-most surface.

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.

Amoeba and yeast are unicellular while spirogyra is multicellular. But all the three reproduce asexually.

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).

A sexual reproduction take place without the process of gamete formation and only one parent is needed, examples include Amoeba reproduce by binary fission (division of cell into two similar cells). Yeast, reproduce by budding (small bud develops from body wall of parent that separate and grow further). Banana, reproduce by vegetative propagation (vegetative parts of a plant such as root, stem etc. can produce new plants) In dog, sexual reproduction take place (i.e. it involves two sexes-male and female whose gametes fuse constituting sexual reproduction).