How does the mass of an object affect the outcome when an unbalanced force acts on it? if you can, can you also simplify it into simple terms that are easier to understand?

By Newton's second law, it reduces the magnitude of the acceleration, without changing its direction.

F = unbalanced force

m = mass

a = acceleration

a = F/m

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.