Assertion (A): The appendix is a vestigial organ. Reason (R): It has no known function in the human body. MCQ with Answer and Explanation

Explanation:
The spleen is the largest lymphoid organ in the body. It is located in the abdominal cavity, specifically in the upper left quadrant, tucked between the stomach and the diaphragm, protected by the rib cage (ribs 9-11). It functions primarily in filtering blood, removing old or damaged red blood cells, storing platelets, and mounting immune responses against blood-borne pathogens. It is not located in the thoracic, pelvic, or cranial cavities.

Explanation:
In prometaphase, the nuclear envelope breaks down, and spindle microtubules attach to kinetochores at the centromeres of chromosomes. This is a crucial step before alignment. In prophase, chromosomes condense; metaphase aligns them at the equator; anaphase separates chromatids. Prometaphase follows prophase in many descriptions.

Explanation:
Scurvy results from vitamin C deficiency, leading to bleeding gums, poor wound healing, and anemia. Vitamin A deficiency causes night blindness, D rickets, B₁ beriberi.