Science MCQs

Malaria is caused by *Plasmodium*, a type of protozoan parasite.

Peyer's patches are lymphoid tissues found in the wall of the small intestine.

Tonsils are located in the throat and often swell when fighting an infection.

Vaccination introduces a weakened or dead pathogen, stimulating the body to produce its own antibodies, which is active immunity.

The spleen acts as a filter for blood, removing old and damaged red blood cells and storing white blood cells.

Bone marrow contains stem cells that differentiate into all types of blood cells,, including those vital for the immune system.

The heart is part of the circulatory system, not the lymphoid system. Lymphoid organs include the thymus, spleen, tonsils, lymph nodes, and bone marrow.

Antibodies circulate until they find and bind to their specific antigen, marking the pathogen for destruction or directly neutralizing it.

Innate immunity provides a rapid, general defense. Adaptive immunity is slower to activate but is highly specific to the pathogen and has memory.

Viruses lack the machinery to replicate on their own; they must hijack the organelles of a host cell to multiply.