Short- Answer Questions for class 8
Question 1. Why is reproduction important?
Answer . It is because of reproduction that life continues from generation to generation.
Question 2. What is menstruation?
Answer . If the ovum is not fertilized by a sperm, it is expelled from the uterus along with some uterine muscles and blood. This is known as menstruation.
Question 3. How does Hydra reproduce:
Answer . Hydra reproduces by budding. In Hydra, a bud appears on the body wall which grows into a full Hydra in a day or two and separates from the parent.
Question 4. How does placenta help the foetus?
Answer . The placenta is responsible for providing oxygen and nutrients and removing waste substances.
Question 5. What is metamorphosis?
Answer . The series of change in an organism during its life cycle that transform it from the larva to an adult.
Question 6. Differentiate between external and internal fertilization?
|Fusion of the gametes takes place outside the body of the organisms.
||Fusion of the gametes takes place inside the body of the organisms.
|Example: In most aquatic animals, such as bony fish
In organisms like reptiles, birds and mammals
Question 7. How is zygote formed in humans? Where is it formed?
The fusion between a male gamete and a female gamete in the oviduct result in the formation of a fertilized egg or zygote in humans. It is formed in the fallopian tube of female.
Question 8. Which two processes are responsible for the development of embryo in multicellular organisms?
In multicellular organisms, development of embryo occurs by cell division and cell differentiation.
Question 9. Explain what happens after a hen lays a fertlised egg?
The hen then sits s on the egg to keep it warm. Development of the chick takes place inside the shell. After its development is complete, the chick comes out by bursting open the egg shell.
Question 10. What is incubation?
The process of keeping the eggs warm in order to hatch is called incubation.
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