The Lac operon in E. coli is an example of an: MCQ with Answer and Explanation

Explanation:
Most bacteria possess a single circular double-stranded DNA molecule located in the nucleoid region. Some bacteria may also have linear chromosomes or multiple chromosomes, but the typical prokaryotic chromosome is circular. Eukaryotes have linear chromosomes. Plasmids are small, circular extra-chromosomal DNA in bacteria.

Explanation:
Ethylene is a gaseous plant hormone that promotes fruit ripening (climacteric fruits like banana, apple), leaf abscission, and senescence. Auxin, gibberellin, and cytokinin primarily promote growth. Ethylene is used commercially to ripen fruits uniformly. It also stimulates the formation of abscission layers and inhibits stem elongation.

Explanation:
Oxytocin, released from the posterior pituitary, increases the frequency and strength of uterine contractions during labor via positive feedback. Prolactin stimulates milk production, estrogen helps uterine growth, relaxin relaxes pelvic ligaments.