What would happen if both natural selection and drift are op

What would happen if both natural selection and drift are operating in a population at the same time? Would the extinction rate increase, decrease, or remain the same?  

Solution

Extinction rate will increase because drift has no effect on large population but if it will occur simultaneously with natural selection then obviously the population size will get smaller.

And as the population size will get smaller the genetic drift will show more drastic effects leading to increase in the extinction rate of a particular population.

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