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In Spirogyra, asexual reproduction takes place by (a) breaking up of filaments into smaller bits (b) division of a cell into two cells (c) division of a cell into many cells (d) formation of young cells from older cells.

a) Breaking up of fragments into smaller bits. Spirogyra undergo vegetative, asexual and sexual reproduction. The life cycle of Spirogyra is... View Article

A feature of reproduction that is common to Amoeba, Spirogyra and Yeast is that (a) they reproduce asexually (b) they are all unicellular (c) they reproduce only sexually (d) they are all multicellular

a) They reproduce asexually b) They are all unicellular Asexual reproduction is a mode of reproduction in which a new offspring is produced by... View Article

Characters that are transmitted from parents to offspring during reproduction show (a) only similarities with parents (b) only variations with parents (c) both similarities and variations with parents (d) neither similarities nor variations

c) Both similarities and variations with parents Characters that are transmitted from parents to offspring shows both similarity and variation.... View Article

Characters transmitted from parents to offspring are present in (a) cytoplasm (b) ribosome (c) Golgi bodies (d) genes

d) Genes The characteristics that are transmitted from parents to offspring are present in genes. Genes are present on chromosomes.The human... View Article

Offspring formed by asexual method of reproduction have greater similarity among themselves because (i) asexual reproduction involves only one parent (ii) asexual reproduction does not involve gametes (iii) asexual reproduction occurs before sexual reproduction (iv) asexual reproduction occurs after sexual reproduction (a) (i) and (ii) (b) (i) and (iii) (c) (ii) and (iv) (d) (iii) and (iv)

(a) (i) and (ii) In sexual reproduction, fusion of male and female gamete takes place. So, mixing of genetic trait occurs in sexual... View Article

Which of the following is the correct sequence of events of sexual reproduction in a flower? (a) pollination, fertilisation, seedling, embryo (b) seedling, embryo, fertilisation, pollination (c) pollination, fertilisation, embryo, seedling (d) embryo, seedling, pollination, fertilization

(c) Pollination, fertilisation, embryo, seedling In flowers, the pollen grain germinates after the pollination of the carpel and grows into the... View Article

In a flower, the parts that produce male and female gametes (germ cells) are (a) stamen and anther (b) filament and stigma (c) anther and ovary (d) stamen and style

(c) anther and ovary The anther is a yellowish, sac-like structure, involved in producing and storing the pollens. Ovary: It is the ductless... View Article

In the list of organisms given below, those that reproduce by the asexual method are (i) banana (ii) dog (iii) yeast (iv) Amoeba (a) (ii) and (iv) (b) (i), (iii) and (iv) (c) (i) and (iv) (d) (ii), (iii) and (iv)

(b) (i), (iii) and (iv) Yeast, reproduce by budding (small buds develop from body wall of parent that separate and grow further). Banana,... View Article

Why is the flow of signals in a synapse from axonal end of one neuron to dendritic end of another neuron but not the reverse?

When an electrical signal reaches the axonal end of a neuron, it releases a chemical substance. This chemical diffuses towards the dendrite end... View Article

“Nervous and hormonal systems together perform the function of control and coordination in human beings.” Justify the statement.

The nervous system controls and coordinates all the functions in the body. It carries out its functions in close coordination with the hormonal... View Article

What are reflex actions? Give two examples. Explain a reflex arc.

Reflex is an involuntary and sudden response to stimuli. It happens to be an integral component of the famed survival instinct.Reflex action is a... View Article

Name various plant hormones. Also give their physiological effects on plant growth and development.

There are four types of naturally occurring plant hormones. These are auxin, gibberellins, cytokinin and abscisic acid. The physiological effect... View Article

Mention one function for each of these hormones : (a) Thyroxin (b) Insulin (c) Adrenaline (d) Growth hormone (e) Testosterone.

(a) Thyroxine hormone regulates carbohydrate, protein and fat metabolism in the body to provide the best balance for growth. (b) Insulin is a... View Article

What constitutes the central and peripheral nervous systems? How are the components of the central nervous system protected?

Central Nervous System : It is hollowed part of nervous system that lies along the mid-dorsal part of the body. It has two parts-brain and... View Article

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Archives

In Spirogyra, asexual reproduction takes place by (a) breaking up of filaments into smaller bits (b) division of a cell into two cells (c) division of a cell into many cells (d) formation of young cells from older cells.

A feature of reproduction that is common to Amoeba, Spirogyra and Yeast is that (a) they reproduce asexually (b) they are all unicellular (c) they reproduce only sexually (d) they are all multicellular

Characters that are transmitted from parents to offspring during reproduction show (a) only similarities with parents (b) only variations with parents (c) both similarities and variations with parents (d) neither similarities nor variations

Characters transmitted from parents to offspring are present in (a) cytoplasm (b) ribosome (c) Golgi bodies (d) genes

Which of the following is the correct sequence of events of sexual reproduction in a flower? (a) pollination, fertilisation, seedling, embryo (b) seedling, embryo, fertilisation, pollination (c) pollination, fertilisation, embryo, seedling (d) embryo, seedling, pollination, fertilization

In a flower, the parts that produce male and female gametes (germ cells) are (a) stamen and anther (b) filament and stigma (c) anther and ovary (d) stamen and style

In the list of organisms given below, those that reproduce by the asexual method are (i) banana (ii) dog (iii) yeast (iv) Amoeba (a) (ii) and (iv) (b) (i), (iii) and (iv) (c) (i) and (iv) (d) (ii), (iii) and (iv)

Why is the flow of signals in a synapse from axonal end of one neuron to dendritic end of another neuron but not the reverse?

“Nervous and hormonal systems together perform the function of control and coordination in human beings.” Justify the statement.

What are reflex actions? Give two examples. Explain a reflex arc.

Name various plant hormones. Also give their physiological effects on plant growth and development.

Mention one function for each of these hormones : (a) Thyroxin (b) Insulin (c) Adrenaline (d) Growth hormone (e) Testosterone.

What constitutes the central and peripheral nervous systems? How are the components of the central nervous system protected?

What are the major parts of the brain? Mention the functions of different parts.

Which endocrine gland is present in males but not in females?

Name the endocrine gland associated with kidneys?

Which gland secretes digestive enzymes as well as hormones?

Name the endocrine gland associated with brain?

Iodine is necessary for the synthesis of which hormone?

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