ANSWER THREE QUESTIONS FROM THIS
1a. Draw a large and neatly labeled diagram of motor neurone.
b. Briefly describe how a nerve impulse is transmitted along a motor neurone.
c. Difine the term reflex action, giving an example.
2a. How does blood function as a transport medium?
b. Describe the mechanism of blood clothing on the side of a wound.
c. A woman who is Rh negative marries a man who is Rh positive.
i. Explain what hapens if her first baby is Rh positive.
ii. Explain what happens to the subsequent pregnancies.
3a. Define the following words:
i. Sexual intercourse
iii. Sex-link genes
b. What are the disadvantages of feeding babies with cow milk?
c. List the signs and symtoms of sexual maturity in humans.
4a. Distinguish between the following pairs of words:
i. Antigens and antibodies.
ii. Active immunity and passive immunity.
b. How is the body naturaly protected from invading pathogens and harmful substances?
c. Suggest why it has not been possible to produce a vaccine for maleria.