Question

1. What is the role of saliva in the digestion of food?

2. what are the difference between aerobic and anaerobic respiration?

Name some organisms that use the anaerobic mode of respiration?

3. Describe double circulation in human beings why is it necessary?

4. What would be the consequences of A deficiency of haemoglobin in our

bodies and what are the difference between the transport of materials in

xylem and phloem?

5. Draw the structure of neurone and explain its functions?

6. Why does menstruation occur? what are the functions performed by the

testis in human beings? What are the different methods of contraception?

7. Two lamps one rated 100 w at 220 v, and other 60w at 220 v, are

connected in parallel to electric means supply.in what current is drawn

from the line if the supply voltage is 220 v?

8. A copper wire has diameter 0.5 mm and resistivity of 1.6 into 10 to the

power minus 8 ohm metre. What will be the length of this wire to make its

resistance 10 ohm ? How much does the resistance change if the diameter

is doubled?

9. How is a voltmeter connected in the circuit to measure the potential

difference between two points?

10.Why is a normal eye not able to see clearly the objects placed closer than

25cm? Explain why the planets do not Twinkle.A concave lens of a focal

length 15cm forms an image 10cm from the lens. How far is the object

placed from the lens? Draw the ray diagram.

11.The magnification produced by a plane mirror is + 1. What does this

mean?

12.Find the focal length of a lens power -2.0 d. What type of lens is this?​

Answer 1

Saliva, the watery liquid produced by glands located under the tongue, is an essential component of the digestive process. Saliva is 98% water, so it moistens the mouth and helps compact food into softened particles for easier swallowing