Over the last several decades, the scientific community has gathered a large amount of information regarding genetics and genetic variation. What are two main sources that lead to increased genetic variation?

Selective breeding

Gamete mutations

Recombination

Genetic drift

You can choose more than 1. I said 1 and 4.
Any help on this?

Question

Over the last several decades, the scientific community has gathered a large amount of information regarding genetics and genetic variation. What are two main sources that lead to increased genetic variation?

 Selective breeding

 Gamete mutations

 Recombination

 Genetic drift

You can choose more than 1. I said 1 and 4. 
Any help on this?

anonymous · Answer

I would say Recombination, because it's new arangement of the Gens, and Genetic drift, because it's coincidence of a genetical mutation in a population. So these two might have the most impact on genetic variation.