Rickets in children is characterized by: MCQ with Answer and Explanation

Explanation:
Pellagra, with the 3 Ds (dermatitis, diarrhea, dementia), is due to deficiency of niacin (vitamin B₃) or tryptophan. Beriberi is B₁, scurvy C, rickets D. Niacin is part of NAD and NADP.

Explanation:
The plasma membrane (cell membrane) is primarily composed of a phospholipid bilayer with embedded proteins, following the fluid mosaic model, regulating transport in and out of the cell. The nucleus is the membrane-bound organelle that houses the cell's genetic material (DNA) organized into chromosomes. Mitochondria are the site of aerobic cellular respiration and ATP production; chloroplasts are the organelles where photosynthesis occurs in plant cells. Thus, statements 1 and 2 are correct.

Explanation:
Alfred Russel Wallace, a British naturalist, independently arrived at the theory of evolution by natural selection. His 1858 essay, sent to Darwin, prompted the joint presentation of their ideas. Darwin then published 'On the Origin of Species' in 1859. Malthus influenced population thinking, Lyell geology, Lamarck earlier evolutionary ideas.