Class 10 Science Chapter 7 MCQ

Here, only one statement is correct. Hence, your answer will be option [A].

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”.

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.

Spores are the microscopic a sexual reproductive body which are covered by a hard-protective coat. This coat enables them to survive under unfavorable condition like lack of food, lack of water and extreme temperatures. But when the conditions are favorable, then the spores grow to produce new plants. Thus, spores are a kind of seeds of plants.

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.

Cracking of voice is associated with second maturation is boys which occurs during adolescence. During teenage a new set of changes occurs in boys and girls. In boys, there are changes includes growth of hair on face, cracking of voice etc. Loss of milk teeth, increase in height and weight gain are the normal process of growth in both boys and girls as the body grows older.

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.

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.

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

Length of pollen tube depends on the distance between pollen grain on upper surface of stigma and ovule. A pollen grain falls on the stigma of the carpel, bursts, open and develops a pollen tube downwards through the style towards the ovule in the ovary.

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

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.

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.

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

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.

In sexual reproduction, the offspring are not identical to the parents or to one another. This is because the offspring receives some genes from mother and some genes from father. Because of mixing of genes on re-establishment of number of chromosome in various different combinations, the off spring show both similarities and variations with characters of parents.

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.

In a flower, the parts that produce male and female gametes are anther and ovary respectively. Stamen is the male reproductive unit of the flower. It contains a bilobed anther at the top which produces male gametes. Filament is the stalk of the stamen that supports anther. Pistil (carpel) is the female reproductive part of the flower. It consists of ovary (forms ovules-female gametes), stigma (receives pollen) and style (elongated tube).