Phenotype refers to which of the following?

• A. The genetic makeup of an organism.
• B. The sequence of nucleotides in DNA.
• C. The observable traits resulting from genotype and environment.
• D. The energy status of a cell.

Answer: (C)

Phenotype is the observable traits of an organism—the characteristics you can see or measure. These traits come from how the organism’s genes are expressed and how the environment influences that expression. The genotype provides the genetic blueprint, but environmental factors like nutrition, temperature, or light can change how that blueprint is realized, leading to the visible traits you observe. Examples include a plant’s height, leaf color, or enzyme activity that you can measure.

The other options don’t describe what phenotype is: the genetic makeup refers to the genotype, the sequence of nucleotides is the DNA code, and energy status reflects the cell’s metabolic condition rather than the outward traits.