What may be the symptoms of a disease if liver is infected ?

Q.

One can be infected with a sexually transmitted disease without experiencing any symptoms.

Q. A person moving through a tuberculosis prone zone has a 50% probability of becoming infected. However, only 30% of infected people develop the disease. What percentage of people moving through a tuberculosis prone zone remains infected but does not show symptoms of disease?

Q. 'X' is a fatal disease which is caused by bite of infected animal.
Symptoms include:Identify 'X'.

Q. A sexually transmitted disease which develops symptoms like chancre on the genitals is caused by the infection of ___.

Q.

(a) List two sexually transmitted disease in each of the following cases:

(i)Bacterial infections

(ii)Viral infections

(b) How may the spread of such diseases be prevented?