The units of inheritance that transmit information.

• A. Genes
• B. Chromosomes
• C. Alleles
• D. Genomes

Answer: (A)

The idea being tested is that inheritance happens through discrete units that carry specific instructions. Those units are genes. A gene is a defined sequence of DNA (or RNA in some organisms) that contains the information to make a functional product, typically a protein or a molecule of RNA, which influences a trait. Because these gene sequences are passed from parents to offspring through reproductive cells, they serve as the carriers of hereditary information from one generation to the next.

Chromosomes are the larger structures that house many genes; they are the means by which genes are organized and transmitted, but the actual units of inheritance are the genes themselves. Alleles are just different versions of a gene, explaining variation, while a genome is the complete set of genetic material in an organism. So the correct concept is that genes are the units of inheritance that transmit information.