A population of animals is split in half by a river. Before speciation is completed, the two halves are rejoined when a drought causes the river to run dry. How would this impact the two population?

Speciation may be defined as the process of formation of new species from a parental one. It occurs when members of similar populations no longer interbreed to produce fertile offspring within their natural environment.

The complete question is as follows:

Traits that had developed through mutation would still exist in only one of the halves.
Speciation would still occur because the two halves would be too different genetically to interbreed.
The two halves would be reproductively isolated.
Gene flow would increase between the two halves, and speciation would not occur.

Speciation requires time for genetic variations and mutations to occur. It makes the organism's reproductive isolated and hence the process of speciation may take place.

Therefore, the correct option for this question is D.

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