Which of the following statements is true?

A. A cells phenotype is determined by its DNA, and its genotype is determined by its proteins
B. A cells genotype is determined by its DNA, and its phenotype is determined by its proteins.
C. A cells genotype is determined by its DNA and its proteins.
D. A cells genotype and phenotype are determined by its proteins

B

Explanation:  Ultimately, one wishes to determine how genes—and the proteins they encode—function in the intact organism. Although it may sound counterintuitive, one of the most direct ways to find out what a gene does is to see what happens to the organism when that gene is missing. Studying mutant organisms that have acquired changes or deletions in their nucleotide sequences is a time-honored practice in biology. Because mutations can interrupt cellular processes, mutants often hold the key to understanding gene function. In the classical approach to the important field of genetics, one begins by isolating mutants that have an interesting or unusual appearance: fruit flies with white eyes or curly wings, for example. Working backward from the phenotype—the appearance or behavior of the individual—one then determines the organism's genotype, the form of the gene responsible for that characteristic. You can also go to https://www.ncbi.nlm.nih.gov/ and https://quizlet.com/ to find other answers.