Which best describes gene expression a. all cells make all types of proteins at all times b. proteins are only made at certain times in certain cellsc. each cell only has the code to make one proteind. a person's phenotype can be different from his or her geneotype

The right answer is: B. Proteins are only made at certain times in certain cells.

Gene expression, also called gene expression or gene expression, refers to the set of biochemical processes by which the hereditary information stored in a gene is read to lead to the production of molecules that will have an active role in cell function. like proteins or RNAs.
Even if all the cells of an organism share the same genome, certain genes are expressed only in certain cells, at certain periods of the life of the organism or under certain conditions.
The genotype determines the characters of an individual, constituting the phenotype, and passes from parents to their descendants. So the genotype and phenotype are closely related and can not differ from each other.

The answer is joseph is observing the colour of the reaction mixture to see whether proteins are present in the given solution.