How have pandemics helped with pollution

Freckles are a dominant trait in humans. both of the girls have the genotype ff for freckles. if either one marries a man with no freckles, what are the chances that their children will have freckles?

In the practice of science, this type of reasoning is used to develop explanations.

There are fewer than 100 naturally occurring elements in the universe, but there are millions of different unified substances. explain how this can be true.