Answer:
They can mate and produce offspring that (are fertile) can mate and produce offspring.
Step-by-step explanation:
A species is defined as a group of similar organisms which are capable of sharing genetic material and interbreeding in nature to produce fertile offspring (offspring which can also reproduce). Emperor penguins are considered a species, because they are able to reproduce to create fertile offspring and continue the spread of their genetic material.
Some rare organisms such as Ligers (Tiger+ Lion) and Mules (Horse + Donkey) Exist and are able to be produced, however, they lack reproductive abilities, so they are not considered a true species.