Which of the following statements about the lymphatic system is correct? MCQ with Answer and Explanation

Explanation:
Humans are ureotelic—they excrete nitrogenous waste mainly as urea, which is less toxic than ammonia and requires moderate water for excretion. Ammonia is excreted by aquatic animals, uric acid by birds and reptiles (to conserve water), and creatinine is also excreted but is a minor component compared to urea.

Explanation:
Diphtheria is a highly contagious bacterial infection caused by Corynebacterium diphtheriae. It primarily affects the mucous membranes of the nose and throat, producing a thick gray pseudomembrane. The bacteria also produce a potent exotoxin that can damage the heart, kidneys, and nervous system. It is preventable by the DPT vaccine.

Explanation:
African sleeping sickness (trypanosomiasis) is caused by the protozoan Trypanosoma brucei, transmitted by the tsetse fly (Glossina). Malaria is by Plasmodium (Anopheles mosquito), filariasis by Wuchereria (Culex), yellow fever by a virus (Aedes). Sleeping sickness affects the central nervous system, causing lethargy, coma, and death if untreated.