What term describes the physical appearance of an organism?

The term that describes the physical appearance of an organism is phenotype. The phenotype encompasses all observable traits, such as height, color, shape, and behavior, resulting from the interaction between an organism's genetic makeup (genotype) and its environment.

In contrast, the genotype refers to the genetic constitution of an organism, specifically the alleles it carries for particular genes. Alleles are different versions of a gene that can produce variations in traits, while chromosomes are structures within cells that contain genetic material. Each of these terms relates to genetics but has a distinct meaning, and understanding the difference is crucial for studying how traits are inherited and expressed in living organisms.