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Which among the following statements are true for unisexual flowers? (i) They possess both stamen and pistil (ii) They possess either stamen or pistil (iii) They exhibit cross-pollination (iv) Unisexual flowers possessing only stamens cannot produce fruits (a) (i) and (iv) (b) (ii), (iii) and (iv) (c) (iii) and (iv) (d) (i), (iii) and (iv)

b) (ii), (iii) and (iv) The flowers which contain only the male or female reproductive organs are called unisexual flowers. They are called... View Article

Which of the following statements are true for flowers? (i) Flowers are always bisexual (ii) They are the sexual reproductive organs (iii) They are produced in all groups of plants (iv) After fertilisation, they give rise to fruits (a) (i) and (iv) (b) (ii) and (iii) (c) (i) and (iii) (d) (ii) and (iv)

d) (ii) and (iv) Flowers are a characteristic of flowering plants i.e., Angiosperms. Other plants like Bryophytes, Pteridophytes and... View Article

Length of pollen tube depends on the distance between (a) pollen grain and the upper surface of the stigma (b) pollen grain on the upper surface of stigma and ovule (c) pollen grain in anther and upper surface of stigma (d) upper surface of stigma and lower part of style

b) Pollen grain on upper surface of stigma and ovule The function of the pollen tube is to carry male gametes towards the ovary through stigma... View Article

Factors responsible for the rapid spread of bread mould on slices of bread are (i) large number of spores (ii) availability of moisture and nutrients in bread (iii) presence of tubular branched hyphae (iv) formation of round shaped sporangia (a) (i) and (iii) (b) (ii) and iv) (c) (i) and (ii) (d) (iii) and (iv)

c) (i) and (ii) The sporangium of bread mould releases numerous spores that germinate on a suitable substratum to form the hyphae. Multiple... View Article

Vegetative propagation refers to the formation of new plants from (a) stem, roots and flowers (b) stem, roots and leaves (c) stem, flowers and fruits (d) stem, leaves and flowers

b) Stem, roots and leaves Vegetative propagation is an asexual method of plant reproduction that occurs in its leaves, roots and stem. This can... View Article

In Rhizopus, tubular thread-like structures bearing sporangia at their tips are called (a) filaments (b) hyphae (c) rhizoids (d) roots

(b) hyphae Rhizopus is a genus of saprophytic and parasitic fungi. They are found in moist or damp places. They are found on organic substances... View Article

The number of chromosomes in parents and offsprings of a particular species remains constant due to (a) doubling of chromosomes after zygote formation (b) halving of chromosomes during gamete formation (c) doubling of chromosomes after gamete formation (d) halving of chromosomes after gamete formation

b) Halving of chromosomes during gamete formation Gametes are formed through a process of cell division called meiosis. This two-step division... View Article

The correct sequence of reproductive stages seen in flowering plants is (a) gametes, zygote, embryo, seedling (b) zygote, gametes, embryo, seedling (c) seedling, embryo, zygote, gametes (d) gametes, embryo, zygote, seedling

a) Gametes, zygote, embryo, seedling The male gamete is present in the pollen grain which is formed by meiotic division in the anther. The... View Article

The ability of a cell to divide into several cells during reproduction in Plasmodium is called (a) budding (b) reduction division (c) binary fission

(d) multiple fission Binary fission is a type of asexual reproduction typically observed in prokaryotes and a few single-celled eukaryotes. In... View Article

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

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