Explanation
The term Heterochromatin was coined by German biologist and cytologist Heitz in the early 1920s. The correct answer is B.
Heitz first observed differences in the staining properties of chromatin in interphase nuclei, and he classified regions of chromatin that stained more intensely as "heterochromatin." In contrast, regions of chromatin that stained less intensely were classified as "euchromatin." Heitz's observations were based on the use of basic dyes, which bind to negatively charged DNA, and he proposed that the differences in staining were due to differences in the chemical composition of chromatin in different regions of the nucleus.
Morgan, Warburg, and Hammerling were all prominent biologists in their own right, but they did not coin the term heterochromatin. Morgan was a geneticist known for his work on fruit flies, Warburg was a biochemist known for his research on cellular respiration, and Hammerling was a developmental biologist known for his work on regeneration in single-celled organisms.
