Which term describes the physical carrier of genes located in the nucleus?

• A. Allele
• B. Codon
• C. Diploid
• D. Chromosome

Answer: (D)

Genes are specific sequences of DNA, and in eukaryotic cells that DNA is organized into structures called chromosomes within the nucleus. These chromosomes are the physical carriers that hold the genes and ensure they are passed on during cell division. Think of chromosomes as the packaging units that bundle long DNA molecules into manageable chunks that can be accurately segregated when cells divide. The other terms describe things related to genes but not the carrier itself: an allele is a variant form of a gene, a codon is a three-nucleotide unit in mRNA that codes for an amino acid, and diploid simply refers to having two sets of chromosomes, not the carrier.