(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.

The main function of epithelial tissue is:

(C) Defense

Explanation:

Epithelial tissue serves as a protective covering for the body and its organs. It acts as a barrier that helps prevent the entry of pathogens and other harmful substances. Epithelial cells are tightly packed and form continuous sheets, providing a protective layer on the body surfaces, both internal and external. This protective function is essential for defending the body against infections and maintaining its integrity. Therefore, option (C) Defense is the correct answer.