The disease caused by deficiency of vitamin D in children is: MCQ with Answer and Explanation

Explanation:
Iodine deficiency leads to insufficient thyroid hormone production, causing TSH hypersecretion and thyroid gland enlargement (goiter). Anemia is iron/B₁₂/folate deficiency, rickets vitamin D, scurvy vitamin C.

Explanation:
Prokaryotic DNA is typically circular, double-stranded, and found in a nucleoid region without a nuclear membrane. It is not associated with histones (though some Archaea have histone-like proteins). Plasmids are extra-chromosomal DNA. Eukaryotic DNA is linear and complexed with histones. This difference is fundamental in cell classification.

Explanation:
The fluid mosaic model, proposed by Singer and Nicolson (1972), describes the plasma membrane as a phospholipid bilayer with proteins floating like icebergs in a sea of lipids. It accounts for membrane fluidity and selective permeability. The cell wall is rigid, nucleus has a double membrane, ribosome is a ribonucleoprotein complex.