<span>Males and females are attracted to each other in order to ensure the viability and fertility of the offspring, which is also why it is uncommon that males of one species be attracted to females of another. Members of two different species cannot mate and thus cannot produce fertile, viable offspring, unless they are part of different sub-species. But they must be part of the same species.
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Their valency is one and both belong to the third period
Explanation:
The traits more sensitive noses is advantageous to the species
