Which of the following best describes a phenotype?

A phenotype refers to the observable characteristics of an organism, which can include physical traits such as height, color, shape, and behavior. These traits result from the interaction between the organism's genotype (the genetic composition) and environmental factors. By focusing on observable characteristics, the concept of phenotype encompasses a wide range of traits that can be measured or seen, making it crucial in fields like genetics, ecology, and evolution.

In contrast, the genetic composition of an organism (the first choice) relates to the genotype, which includes all the alleles present but does not directly describe how those alleles manifest as physical traits. The alleles carried by an organism (the third choice) refer specifically to the different forms of a gene and do not provide a complete picture of observable traits. Finally, potential genetic variations (the fourth option) refer to the ability for a population's genetic makeup to change over time, which is a broader concept that does not focus on the specific traits an individual exhibits.