The substance that causes the clotting of blood is:

(A) Thrombin

Thrombin is an enzyme that plays a crucial role in the blood clotting process. It is responsible for converting fibrinogen, a soluble plasma protein, into insoluble fibrin threads. These fibrin threads form a mesh that helps in the clotting of blood, particularly at the site of injury or wound. Therefore, option (A) Thrombin is the correct answer.

Mammals are a common source of fibre.

1. Embers Goat

3. Llama

4. Alpaca

(B) Spleen

The organ primarily affected by malaria is the spleen. Malaria is a parasitic infection caused by Plasmodium parasites that are transmitted through the bites of infected mosquitoes. The parasites multiply in the liver and then infect red blood cells, leading to symptoms such as fever, chills, and an enlarged spleen. The spleen plays a crucial role in the immune response against malaria, but the infection can cause it to enlarge as it filters out infected red blood cells from the circulation. If left untreated, severe cases of malaria can lead to complications, including damage to the spleen and other organs.

(D) Kwashiorkor

Kwashiorkor is a disease caused by a deficiency of protein in the diet. It often occurs in areas where there is a lack of access to an adequate protein source. The condition is more common in developing countries and can affect children, leading to symptoms such as swelling (edema), a distended abdomen, stunted growth, and changes in skin and hair. Protein is essential for the proper growth and maintenance of tissues in the body, and a lack of it can result in severe health issues, as seen in the case of kwashiorkor. Scurvy, Beri-Beri, and Night-Blindness are caused by deficiencies of vitamin C, thiamine (vitamin B1), and vitamin A, respectively, not protein.