In a controlled scientific experiment,
a. only one variable can be kept constant.
b. no variables are kept constant.
c. all variables are kept constant.
d. one or more variables are kept constant.

Suppose a point mutation, such as a change from an adenine to a guanine, occurs in the genome of a human sperm cell. the mutation could occur in any region of a gene. the effect of the mutation on the phenotype of the offspring will be determined by where the mutation occurs and its effect on the final gene product. in which of the following scenarios could the mutation alter the phenotype of the offspring? select all of the scenarios that apply the mutation occurs in the promoter and affects the rate of gene transcription. the mutation results in a new, dominant allele the mutation occurs in a portion of an intron not responsible for exon splicing the mutation occurs in a gene that controls development and alters differentiation of a cell type during development. the mutation occurs in a codon and alters the function of the final protein e mutation occurs in a codon, and the amino acid sequence of the final protein is unchanged.