NCERT science solutions are based purely on the exercise questions published in NCERT class 8 science textbook. Students can look up answers of their textbook and understand the concepts much better and prepare for their examinations.
CBSE NCERT Solutions for Class 8 Science Chapter 9:
Describe the process of fertilization in human beings.
Fertilization involves the fusion of the male and the female gamete. The male and
the female gametes are released from the male and the female reproductive organs. Sperms or male gametes are released from the male reproductive organ i.e., the penis. These sperms then enter the female body through the vagina. Then, they travel through the fallopian tubes which serve as site for fertilization. Hence, the process of fertilization takes place in the fallopian tubes. During fertilization, the haploid nucleus of the sperm and that of the ovum fuse with each other to form the zygote. This zygote divides to form an embryo which in turn develops
into a fetus.
Define asexual reproduction. Describe two methods of asexual reproduction in animals.
Asexual reproduction is that type of reproduction in which only single parent
is involved. Asexual reproduction takes place by different methods like Budding, Binary fission etc.
→ Budding: This type of reproduction takes place in Hydra and Bacteria. A part of the organism starts bulging out. Slowly it grows and develops into a separate individual.
→ Binary fission – In this type of reproduction, a single organism gets divided into two. This type of reproduction takes place in Amoeba. The nucleus of the Amoeba gets divided into two followed by division of their bodies, each part getting one nucleus and developing into a separate individual.
Indicate whether the following statements are True (T) or False (F).
(a) Oviparous animals give birth to young ones. ( )
(b) Each sperm is a single cell. ( )
(c) External fertilization takes place in frogs. ( )
(d) A new human individual develops from a cell called gamete. ( )
(e) Egg laid after fertilization is made up of a single cell. ( )
(f) Amoeba reproduces by budding. ( )
(g) Fertilization is necessary even in asexual reproduction. ( )
(h) Binary fission is a method of asexual reproduction. ( )
(i) A zygote is formed as a result of fertilization. ( )
(j) An embryo is made up of a single cell. ( )
(a) False (b) True (c) True (d) False (e) True (f) False (g) False (h) True (i) True (j) False