Aspecies is a group of individual organisms that interbreed and produce fertile, viable temporal isolation can result in species that are physically similar and may even in another postzygotic situation, reproduction leads to the birth and growth of a

Members of a species share similar DNA make up that make them compatible to interbreed and reproduce successfully. For two group of individuals to be considered of same species, they must be able to interbreed and produce offspring that are fertile and viable. E.g. a horse and a donkey are two different species that cannot interbreed and reproduce offspring that are viable and fertile. These two species have been said to be interbred but produced an offspring known as the mule, which is sterile and not fertile.

Temporal isolation is a type of prezygotic reproductive barrier that occurs when two populations of a species have different breeding seasons, and so, cannot meet to interbreed to produce offspring, even though they may be dwelling in the same habitat.

Postzygotic barriers as another reproductive barrier are mechanisms that prevent successful reproduction after zygote has been formed from fertilization. Two situations usually arise in postzygotic barriers:

1. The hybrid formed after fertilization in form of zygote, dies at the embryonic stage. This situation is referred to as hybrid inviability.

2. The hybrid formed after fertilization in form of zygote develops and survives both is sterile and unable to reproduce offspring of their kind. This situation is referred to as hybrid sterility.

d. making up measurements to record.