Class 10 Science Chapter 7 MCQ

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

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

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

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

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.

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.

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

Sexual reproduction creates variation in organisms. So, clones cannot be produced through it. Clones are identical copy of parent organism. Sexual reproduction needs two types of “Gametes” i.e. male and female to form zygote after fertilization.

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.

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.

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.

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.

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.

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

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.

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).

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).

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).