Which of the following statements about genes is incorrect? a. During fertilization, both the sperm and the ovum contribute genes to the resulting fertilized egg. b. Many genes contain the information needed for cells to synthesize enzymes and other proteins. c. Genes correspond to segments of DNA. d. Under normal circumstances, each chromosome contains precisely one gene. e. Genetic differences can result from changes in the DNA called mutations.

The correct answer will be option D.

Explanation:

Genes are the coding sequence of the DNA which codes for specific proteins required for a function.

These genes are present physically as the segments on the DNA. These genes are important to an organism as they control a specific trait like the color of flowers and skin of a human.

The genes are located on a site called "locus' on pair of homologous chromosomes that is one on each chromatid. The number of genes varies from chromosomes that are genes can be present in a large number on a single chromosome.

These genes become functional only after they find a complementary pair on the chromosomes, the reason parents need to donate their genes during fertilization.

Thus, option D is the correct answer.

d. Under normal circumstances, each chromosome contains precisely one gene.

Explanation:

The gene is a segment of a DNA molecule, responsible for genetically inherited traits. Each gene consists of a specific DNA sequence that contains a code (instructions) to produce a protein that performs a specific function in the body. Each human cell has about 25,000 genes.

The genes are located within the chromosomes. A chromosome can house thousands of genes, it is not normal for a chromosome to house a gene or a few units. Thus, if a cell contains 46 chromosomes, that cell has an incalculable number of genes.