Final answer:
Chromosomes are best described as structures that carry the codes for hereditary traits. Humans have 46 chromosomes, arranged in 23 pairs, including autosomes and sex chromosomes. The correct option is c.
Step-by-step explanation:
The question asks which statement best describes chromosomes. The correct answer is "c. chromosomes carry the codes for hereditary traits." Humans typically have 46 chromosomes in every somatic cell, organized into 23 pairs. Each pair of chromosomes is composed of one chromosome from each parent, making them homologous.
Chromosomes contain genes which are responsible for the hereditary traits that are passed down from parents to offspring. These traits define both the genotype and phenotype of an individual.
The human chromosomes include 22 pairs of autosomes and one pair of sex chromosomes (XX in females, XY in males). Option c. is the correct one.