Explain the following :
(a) How does the middle ear help in hearing ?
(b) Why does vitamin A deficiency produce night-blindness ?
(c ) What is the role of lacrimal gland ?
(d) How does the iris adjust the size of the pupil ?

Answer the following : (a)Explain how different techniques help cancer detection and diagnosis. (b)How doe smoking cuase oxygen deficiency in the body?

Answer the following : How does lightning improve the fertility of soil and helps produce ozone gas?

Answer the following : How does sound from a sound producing body travel through air to reach our ears?

Answer briefly: (a) Why are villi present in the intestine and not in the stomach? (b) How does pepsinogen change into its active form? (c) What are the basic layers of the wall of alimentary canal? (d) How does bile help in the digestion of fats?

Answer briefly: (a) Why are villi present in the intestine and not in the stomach? (b) How does pepsinogen change into its active form? (c) What are the basic layers of the wall of alimentary canal? (d) How does bile help in the digestion of fats?

Answer briefly: (a) Why are villi present in the intestine and not in the stomach? (b) How does pepsinogen change into its active form? (c) What are the basic layers of the wall of alimentary canal? (d) How does bile help in the digestion of fats?

Answer briefly: (a) Why are villi present in the intestine and not in the stomach? (b) How does pepsinogen change into its active form? (c) What are the basic layers of the wall of alimentary canal? (d) How does bile help in the digestion of fats?

Answer briefly: (a) Why are villi present in the intestine and not in the stomach? (b) How does pepsinogen change into its active form? (c) What are the basic layers of the wall of alimentary canal? (d) How does bile help in the digestion of fats?

(a) Name the chief proteins in milk. (b) How does milk coagulate? (c) What is the product of milkcoagulation? (d) Why milk is not considered as balanced food of adults?

What is lightning (b) How do the clouds get electrically charged ? (c) How does lightning strike a building ?