Answer:
they can naturally interbreed to produce a fertile offspring
F is your answer. Transform Boundary
Well, using Math to see how far the Moon is from the Earth could be hard. Also, he saw that the Moon is moving in a "circle" instead of flying off, so the Earth did have a pull on the Moon so that it didn't fly away. Newton had to use Math in order to be able to identify what it's now called gravity. There's a lot that the Moon has to offer, there were no computers back then, so there's was no calculator and everything had to be done by hand.
He was studying genetics by performing mating crosses in pea plants. Then, he discovered that the traits in the offspring didn't always match the traits in the parental plants.
