When is genetic drift a major factor of evolution?

When there is low gene flow

When there is a lower genetic flow.

Explanation:

Genetic drift is a major factor of evolution when the organism population size is small. In such a population, the random change in the allele frequency that is not a response to a selective pressure can become fixed in a population. The random change in population is called genetic drift.

The genetic drift is a major factor in evolution when there is lower gene flow and when there is no selective pressure and when there is a bottleneck in the environment.

not necessarily. higher fitness requires the organism to be reproductive successful. for example, an organism at age 10 with 15 offspring is much more fit than an organism at age 15 with only 5 offspring.

yes we can.   a lady urinates from her urethra.