Our current understanding of evolution is called a theory because it has been
supported repeatedly as new discoveries have been made.
proven to be exactly true as originally proposed.
corroborated by data that were gathered during a
single experiment.
developed from the postulates of many scientists.

an organism's phenotype is the  form of a trait  that it  displays. for  flowercolor, a pea  plant  can  display  a phenotype of purple or white flowers. an organism's  genotype  is the alleles of a gene it contains. based on his data, mendel concluded that a phenotype can be  determined  by more than one  genotype.