Which type of reproduction lead to increased genetic variation on a population?

Which animal group is the largest and contains more species from all the other living groups combined? is it mammals or

Which would best keep the oxygen cycle stable? a. cutting down jungles to create farmland b. eliminating parks in large cities c. dumping toxic chemicals into the ocean d. reducing the amount of deforestation d. reducing the amount of deforestation

Ascientific idea becomes valid when it is what?