Consider statements about vitamins: 1. Vitamin A is essential for vision. 2. Vitamin C is a fat-soluble vitamin. 3. Vitamin D deficiency causes rickets. Which are correct? MCQ with Answer and Explanation

Explanation:
Pleiotropy occurs when one gene influences several distinct phenotypic traits. Example: phenylketonuria (PKU) caused by a single gene defect leads to mental retardation, light skin color, and musty odor. Polygenic inheritance is many genes affecting one trait, epistasis is gene interaction, multiple alleles are more than two alleles for a gene.

Explanation:
The hypothalamus is the primary thermoregulatory center, maintaining body temperature through sweating or shivering. The cerebellum coordinates voluntary movements, ensuring smooth and accurate muscle activity and balance. The medulla oblongata contains vital reflex centers controlling involuntary actions such as swallowing, coughing, sneezing, and vomiting. All three statements are anatomically and physiologically correct.

Explanation:
Prokaryotes lack membrane-bound organelles like mitochondria, Golgi apparatus, and endoplasmic reticulum. They have 70S ribosomes, a single circular chromosome in a nucleoid, and typically a cell wall (except Mycoplasma). Eukaryotes possess membrane-bound organelles. This fundamental difference defines the two major cell types in the living world.