You discover a binary star system in which one member is a15MSun main-sequence star and the other star is a 10MSun giant. How do we believe that a star system such as this might have come to exist?

Explanation:

The giant star must have at least once been the more massive star and then subsequently transferred some of its mass to its companion, the other star.

The two stars would be around the same age, so the more massive one would have turned into a giant first before the other one did or even had a chance to

the skeletons of most mammals reach a certain size and then stop growing. however, many animals, including some mammals, keep growing throughout their lives. kangaroos, for example, just keep growing and growing until they die. also, the longer an animal lives the greater the chance it might catch some deadly disease.