If two individuals have a certain phenotype, does that mean they must have the same genotype.

Not necessarily. Phenotype is the observable physical or biochemical characteristics of an organism, while genotype refers to the genetic makeup or set of genes an organism carries. Two individuals can have the same phenotype but different genotypes. This can happen due to different genetic mutations or variations that still result in the same observable trait. Moreover, other factors like environmental influences or epigenetic modifications can also affect the phenotype without altering the genotype.