The AB blood group in the ABO system is an example of: MCQ with Answer and Explanation

Explanation:
Drosophila melanogaster (fruit fly) is a widely used model organism in genetics due to its short life cycle, large polytene chromosomes, easy culture, and high fecundity. Thomas Hunt Morgan established its use, discovering linkage and chromosomal theory. Musca domestica is housefly, Periplaneta cockroach, Bombyx silkworm. Many Nobel-winning genetic discoveries were made using Drosophila.

Explanation:
DNA fingerprinting (DNA profiling) is a technique used to identify individuals based on their unique DNA patterns. It primarily relies on the analysis of Variable Number Tandem Repeats (VNTRs) or Short Tandem Repeats (STRs), which are highly polymorphic, non-coding, repetitive DNA sequences that vary greatly in length and number between individuals.

Explanation:
In a closed circulatory system (e.g., humans, annelids, cephalopods), blood is always enclosed within vessels (arteries, veins, capillaries) and is distinct from interstitial fluid. Open systems (arthropods, most mollusks) have hemolymph bathing organs in sinuses. The lymphatic system returns fluid to blood. A portal system connects two capillary beds.