Human Health and Disease

Chronic use of alcohol damages the liver and causes cirrhosis; it also damages the nervous system.

Cellular barriers of innate immunity are leukocytes such as polymorpho-nuclear leukocytes (neutrophils), monocytes, natural killer cells and macrophages, which phagocytose and destroy microbes.
Mucus coating is a physical barrier, while HCl, saliva and tears are physiological barriers.
Anti-tetanus and anti-snake-venom injections contain preformed antibodies, which give passive immunity.

Pneumonia is caused by bacteria such as Streptococcus pneumoniae and Haemophilus influenzae, which infect the alveoli of the lungs; the alveoli fill with fluid.
Common cold is caused by rhinoviruses, which infect the nose and respiratory passage but not the lungs.
Both are communicable diseases, so the other statements are wrong.

Typhoid fever, caused by Salmonella typhi, is confirmed by the Widal test.
HIV infection is detected by ELISA.

Normal cells show contact inhibition: contact with other cells stops their uncontrolled growth.
Cancer cells have lost this property. They divide in an uncontrolled manner, form tumours, compete with normal cells for nutrients and spread to other sites (metastasis).
So showing contact inhibition is not a property of cancerous cells.

Gametocytes taken up with the blood meal fuse in the gut (stomach) of the female Anopheles mosquito.
The zygote formed is motile and is called the ookinete; it penetrates the stomach wall and forms an oocyst.
Sporozoites formed later migrate to the salivary glands.