chapter 1 Indicate the answer choice that best completes the statement or answers the question. 1. A form of a gene that has a slightly different sequence than other forms of the same gene but encodes the same type of an RNA or protein is called a(n) a. locus. b. allele. c. homologous chromosome. d. heterozygote. e. homozygote. 2. How do DNA and RNA differ? a. DNA contains the nitrogenous base thymine while RNA contains the base uracil instead of thymine. b. DNA contains the nitrogenous base guanine while RNA contains the base cytosine instead of guanine. c. DNA is composed of repeating units called nucleotides while RNA is composed of repeating units called amino acids. d. DNA is composed of repeating units called amino acids while RNA is composed of repeating units called nucleotides. e. In DNA the nucleotides contain a sugar, a base, and a phosphate while in RNA the nucleotides contain no sugar. 3. Permanent, heritable changes in genetic information (DNA) are called a. evolution. b. defects. c. SNP. d. alleles. e. mutations. 4. Assume that a geneticist is doing a study with a wild mouse species. She captures 100 of these mice, takes a DNA sample from each