Final answer:
The phenotype of an organism is determined by the genes that are expressed in response to specific environmental conditions and epigenetic factors, leading to observable traits. The genotype provides the genetic information, but environmental influences and epigenetic changes play significant roles in shaping the phenotype.
Step-by-step explanation:
An Organism's Phenotype
An organism's phenotype depends on the specific combination of inherited genes that are expressed under particular environmental conditions. An organism's traits are determined by the specific combination of inherited genes. When addressing the question asked by the student, the correct answer is B) Genotype, environment, and epigenetics. The genotype represents the genetic makeup of an individual, while the phenotype is the set of observable characteristics that result from gene expression influenced by environmental conditions and epigenetics.
For example, sun exposure is an environmental factor that can influence skin color. Similarly, for some organisms, environmental factors like temperature can determine sex - a process known as temperature-dependent sex determination.
The central dogma of molecular biology states that DNA encodes RNA, and RNA encodes for proteins, which are vital for cell functionality. However, not all DNA segments are actively coding for proteins at the same time; this selective expression leads to a diversity in phenotypes even among organisms with the same genotype. Therefore, phenotype is a result of the complex interaction of genetic information, environmental influence, and epigenetic modifications.