Answer:
If two similar looking species are able to produce fertile and viable offspring, then they belong to the same species.
Explanation:
According to the biological species concept , organisms are said to be of same species if they are able to interbreed and produce fertile and viable offspring.
In case if two species are closely related on the basis of external features, then they must be allowed to mate. The offspring produced in the first generation mating must be allowed to mate again. If in the second generation offspring are produced, then it shall prove that the two similar looking organisms are able to produce viable and fertile offspring thereby establishing the fact that they belong to same species.
A gene is a basic unit of heredity and a sequence of nucleotides in DNA that encodes the synthesis of a gene product, either RNA or protein. For example, if both of your parents have green eyes, you might inherit the trait for green eyes from them.
Yes this is true. The Punnett square can be used for such purposes