What causes interference patterns?

Answer/Explanation: Path difference of interfering light rays divided by the light's wavelength. The orders of interference considered most often are those equal to integers—that is, where the path difference is an integral number of wavelengths—because the interference effect is strongest in such cases.

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.