What is a chromosome?

A chromosome is correctly defined as a structure composed of DNA and protein that contains genetic information. This definition accurately captures the fundamental role of chromosomes in genetics, as they serve as the carriers of genetic material in living organisms. Each chromosome consists of a long DNA molecule that is tightly coiled around proteins known as histones. This organization is crucial for DNA packaging within the cell nucleus and also for the proper distribution of genetic material during cell division.

The presence of both DNA and protein within a chromosome is essential for several processes. The DNA holds the genes, which determine inherited characteristics, while the associated proteins play key roles in maintaining the structure of the chromosome, regulating gene expression, and ensuring the correct segregation of chromosomes during cell division.

While the other options mention structures related to cellular function, they do not accurately describe a chromosome. The focus on the combination of DNA and protein in option B is what makes it the correct answer, highlighting the chromosomal role in storing and transmitting genetic information.