What are large and complex molecules of DNA that occur in every body cell called?

The large and complex molecules of DNA that occur in every body cell are called chromosomes. These structures are made up of DNA tightly coiled and packaged around proteins called histones, which help maintain the DNA's structure and regulate its function. Each chromosome contains many genes, which are segments of DNA that encode instructions for building proteins and determining various traits of the organism.

In humans and most animals, chromosomes are found within the nucleus of eukaryotic cells. Each somatic (body) cell typically contains two sets of chromosomes, one from each parent, totaling 46 in humans. The presence of chromosomes is essential for the proper distribution of genetic material during cell division, ensuring that each new cell receives the correct amount of DNA.

Looking at the other options, chromatids refer to the two identical halves of a chromosome that are formed during cell division but are not a separate type of DNA molecule themselves. Eukaryotes describe a broad classification of organisms whose cells have a nucleus, which includes animals, plants, and fungi, rather than specifically referring to DNA structures. Gametes are the reproductive cells (sperm and egg) that contain half the number of chromosomes and are involved in sexual reproduction. Thus, the correct identifying term for the large and complex DNA