Biology STAAR (State of Texas Assessments of Academic Readiness) Practice Test

Which term describes the physical traits that can be observed in an organism?

1. Genotype

2. Phenotype

3. Allele

4. Chromosome

The correct answer is: Phenotype

The term that describes the physical traits of an organism is phenotype. Phenotype encompasses all observable characteristics, including morphology, development, and behavior, which result from the interaction of an organism's genotype with the environment. For instance, if an organism has a genotype for flower color, the phenotype will reflect the color of the flowers that are visibly expressed. In contrast, genotype refers specifically to the genetic makeup of an organism, which may not always be observable. Alleles are different forms of a gene that might determine specific traits, and chromosomes are structures that organize DNA within cells but do not directly describe observable traits. Overall, recognizing the distinction between genotype and phenotype is vital for understanding traits in biology.