What is the relationship between genes, chromosomes, and DNA?
A. A chromosome is composed of a DNA molecule and each chromosome contains multiple genes
B. A gene is composed of chromosomes and each gene contains many DNA molecules.
C. DNA is composed of chromosome and each DNA molecule contains many genes
D. A chromosome is composed of many genes and each DNA molecule is made up of many chromosomes.
E. A gene is composed of many DNA molecules that are composed of chromosomes.

Hint: Chromosomes are made up of chromatin. Chromatin made up of the threads of DNA forms the structure of chromosomes. The DNA gets condensed to form chromosomes. Genes are the segments of DNA. The code for proteins. This means chromosomes are made up of DNA which contains many genes in the form of segments.

Complete answer:
Humans have Genes that consist of deoxyribonucleic acid (DNA). There are about 20,000 to 23,000 genes in the human body. DNA comprises the code, or blueprint used to synthesize a protein. The size of Genes varies and depends on the sizes of the proteins for which they code. The structure of Each DNA molecule is a long double helix that resembles a spiral staircase and contains millions of steps. These steps of the staircase have pairs of four types of molecules called bases (nucleotides). These bases are paired as follows- the base adenine (A) is paired with the base thymine (T), the base guanine (G) is paired with the base cytosine (C). Every extremely long DNA molecule is coiled up inside one of the chromosomes.
The very long strand of DNA which further contains many genes (hundreds to thousands) makes up a chromosome. The genes are arranged in a particular sequence and have a particular location on the chromosome (called its locus). In addition to DNA, chromosomes also contain many other chemical components. These chemicals influence the gene function

So, the correct answer is A.

Note:
Genes are contained in chromosomes. These in the cell nucleus. A single chromosome contains hundreds to thousands of genes. Every normal human cell comprises 23 pairs of chromosomes that mean a total of 46 chromosomes. A trait is any gene-determined characteristic. It is often determined by more than one gene. Whereas, some traits are also caused by mutated genes that are inherited or that are the result of a new gene mutation.