Final answer:
A species is a group of organisms that can interbreed and produce fertile offspring. True-breeding individuals within a species have identical alleles for certain traits, consistently passing these on to their offspring.
Step-by-step explanation:
The original question seems to be about the concept of species in biology. A species is defined as a group of individual organisms that can interbreed with one another and produce fertile offspring. When a group of identical individuals consistently produces offspring of the same phenotype when mated with each other, they are likely representatives of the same species. This is because species members share significant genetic similarities and maintain these characteristics through reproduction.
It's important to note that within a species, individuals may be true-breeding or homozygous for certain traits, meaning they possess two identical alleles for a trait and will produce offspring that also carry these alleles. For example, the P1 parental generation in Mendel's experiments were homozygous plants that always bred true for the traits being studied. Therefore, true-breeding individuals that always produce offspring with the same phenotype are following the principle Mendel discovered.