The forelimbs of humans, whales, and bats exhibit similarity in basic structure due to common ancestry. This is an example of: MCQ with Answer and Explanation

Explanation:
Vitamin D (cholecalciferol) is unique as it can be synthesized in the skin from 7-dehydrocholesterol in the presence of UV-B radiation. It acts as a hormone to regulate calcium and phosphate homeostasis. It must be activated in the liver and kidneys. It is also obtained from dietary sources like fatty fish, egg yolk. Deficiency causes rickets/osteomalacia.

Explanation:
Gel electrophoresis is a widely used technique to separate charged molecules, primarily DNA, RNA, or proteins, in an electric field through a gel matrix (usually agarose for DNA). DNA fragments are separated based on their size (length in base pairs). Smaller fragments move faster and further through the gel than larger ones. The separated DNA bands are visualized using ethidium bromide and UV light.

Explanation:
Codominance occurs when two different alleles of a gene are fully and equally expressed in the heterozygous condition. In the ABO blood group, the IA and IB alleles are codominant. An individual with the genotype IAIB produces both A and B antigens on the surface of their red blood cells, resulting in the AB blood type. While the ABO system also involves multiple alleles (IA, IB, i), the specific expression of both antigens is codominance.