What part of an original isotope’s number of atoms remains have two half-lives?

Several kinds of bears are found on earth. most bears are brown or black, but one type of bear, the polar bear, is white. what process led to this difference in fur color? explain your answer.

Ineed this asap part i: scientific method what is the difference between science and pseudoscience? what is the scientific method?

Which material burns faster? metal aluminum