(a) What is the gestation period? How much is the gestation period in humans?
(b) Name one method of contraception which also protects against sexually transmitted diseases.
(c) Name one sexually transmitted disease for which no definite cure has been found so far. What is the causative organism of this disease?

Q. (a) Name the three types of methods usually used for birth control. Describe each method briefly.
(b) What is meant by sexually transmitted diseases? Name any two sexually transmitted diseases and their causative organisms.
​(c) Which method of contraception can prevent sexually transmitted diseases?

Q. Name the protozoan parasite that causes amoebic dysentery in humans. Mention two diagnostic symptoms of disease. How is this disease transmitted to others ?

Q. Name the causative germ of AIDS. How is this disease transmitted?

Q. (a) What are sexually transmitted diseases? Give two examples of sexually transmitted diseases.
(b) Which method of contraception prevents fertilised egg from being implanted in the uterus?

Q.

There are four tiny organisms A, B, C and D. The organism A is a parasitic protozoan which causes a disease known as kala-azar. The organism B is a microscopic single-celled animal which causes malaria disease in human beings. The organism C is a unicellular animal which can change its body shape according to need, it has no fixed shape. The organism D is also a unicellular animal which is slipper-shaped having a large number of tiny hair all around its body.
(a) Name the organisms A, B, C and D
(b) Name one characteristic body feature of organism A.
(c) Name the insect which carries organism B and transmits it from one person to another.
(d) What name is given to the asexual method of reproduction of (i) organism A, and (ii) organism B?
(e) Where do organisms C and D live?