Which of the following statements about protein synthesis is correct? MCQ with Answer and Explanation

Explanation:
Selective permeability means the membrane controls entry and exit of substances based on size, charge, and solubility. R defines this property and explains A.

Explanation:
Melanocyte-Stimulating Hormone (MSH) is a peptide hormone produced primarily by the intermediate lobe of the pituitary gland (pars intermedia), though in humans, this lobe is rudimentary and MSH is mainly derived from the cleavage of pro-opiomelanocortin (POMC) in the anterior lobe. Its primary function, especially in lower vertebrates like amphibians and reptiles, is to stimulate the melanocytes in the skin to produce and disperse melanin, the pigment responsible for skin, hair, and eye color, leading to darkening of the skin. In humans, its role in pigmentation is less significant.

Explanation:
Charles Darwin proposed the theory of evolution by natural selection, where organisms with favorable traits survive and reproduce. Homologous organs share a common structural plan and evolutionary origin, indicating divergent evolution from a common ancestor. Evolution does not lead to perfection; it only results in adaptation to the current environment. Thus, statements 1 and 3 are correct.