'Microsatellite DNA' is used in the case of which one of the following?

(a) Studying the evolutionary relationships among various species of fauna
(b) Stimulating ‘stem cells’ to transform into diverse functional tissues
(c) Promoting clonal propagation of horticultural plants
(d) Assessing the efficacy of drugs by conducting series of drug trials in a population

Explanation:

Microsatellites, also known as short tandem repeats (STRs) or simple sequence repeats (SSRs), are small regions of repetitive DNA where a specific sequence of 2-6 base pairs is repeated typically 5-50 times. They are found throughout the genome in many organisms, including humans.

Microsatellites mutate at a high rate, which means they can rapidly change and evolve. Because of this high mutation rate, different individuals and different species often have different numbers of repeats at the same microsatellite location. These differences can be used as genetic markers to distinguish between individuals within a species (for example, in forensic DNA fingerprinting) or to study genetic relationships and evolutionary history among different species.

So, microsatellite DNA can be used for studying the evolutionary relationships among various species of fauna (option a). It’s not typically used in stimulating stem cells (option b), promoting clonal propagation of plants (option c), or in drug trials (option d).