Listen NCERT Audio Books to boost your productivity and retention power by 2X.
State whether the following statements are True of False :
(a) Each sperm is a single cell.
(b) A new human individual develops from a cell called gametes.
(c) Egg laid after fertilization is made up of a single cell.
(d) A zygote is formed as a result of fertilization.
(e) External fertilization takes place in frog.
(f) An embryo is made up of a single cell.
(g) Oviparous animals give birth to young ones.
(h) Internal fertilization takes place in hens.
(i) The hens give birth to chicks like human beings give birth to babies.
(j) Amoeba reproduces by budding.
(k) Binary fission is a method of asexual reproduction.
(l) Fertilisation is necessary even in asexual reproduction.
(m) Cloning is a sexual reproduction method in mammals.
Fill in the following blanks with suitable words:
(a) The process of …………. ensure continuity of life on earth.
(b) The cells involved in sexual reproduction are called ……………..
(c) Fusion of gametes gives rise to a single cell called ………..
(d) The process of fusion of gametes is called ……..
(e) The other name of egg cell is …………….
(f) A sperm is much ………………. than an egg cell.
(g) In humans, one nature egg (or ovum) is released into oviduct every ………. by one of the ovaries.
(h) The egg laying animals are called ………… animals.
(i) The cow is a ………… animal whereas ostrich is an …………………. animal.
(j) The change of caterpillar into an adult silk moth is called ……………….
(k) The larva of frog is called ………….
(l) The two common methods of asexual reproduction in animals are ………. and …………………
(m) Dolly , the sheep, was produced by the technique called ………………….
Two very small organisms X and Y both reproduce by the method of budding. Organism X is industrially very important because it is used in making alcohol from sugar. It is also used in making bread. Organisms Y is a tiny animal having tentacles which live in water.
(a) What is organisms X?
(b) Name the process in which X converts sugar into alcohol.
(c) To which class of organism does X belong?
(d) What are organisms Y?
(e) Out of X and Y, which organism is multicellular and which one is unicellular?
A unicellular organism P lives in pond water. The organisms P has no fixed shape, its shape keeps on changing. It moves and catches its prey with the help of organs Q which keep on appearing and disappearing. The organisms P reproduces by a process R. Another organisms S also reproduces by this process. Name P, Q, R and S.
The animal A which is classified as an amphibian lays eggs in pond water. The hatching of its eggs produces a tailed-form B which looks very different from the animal A. The form B then undergoes a change C and gets converted into animal A.
(a) Name (i) animal A and (ii) form B.
(b) What is the change C known as ?
(c) name the breathing organs of A.
(d) What are the breathing organs of B?
X and Y are the two types of animals. The animals like X undergo external fertilization whereas animals like Y undergo internal fertilization. The animals like X lay eggs from which baby animals are hatched. On the other hand, in animals like Y, the young one develops inside the uterus of mother which then gives birth to the baby.
(a) What is the general name of animals like X ?
(b) Give two examples of animals like X ?
(c) What is the general name of animals like Y ?
(d) Write the names if two animals like Y.
A is an insect which breeds in ponds of stagnant water. The egg of this insect produces a worm like form B which is entirely different in appearance from the adult insects. The form B undergoes a change C and gets converted into insects A. The female of insects A is a carrier of protozoan D which spreads a disease in humans.
(a) What are A, B, C, and D ?
(b) Name another insect which also undergoes change C.