A rotator cuff strain is a tear to any of the four rotator cuff muscles in the shoulder and is common in throwing and racket sports.
Natural selection is one of the basic mechanisms of evolution, along with mutation, migration, and genetic drift. Darwin's grand idea of evolution by natural selection is relatively simple but often misunderstood. To find out how it works, imagine a population of beetles: 1  There is variation in traits. 2  For example, some beetles are green and some are brown. 3  There is differential reproduction. 4  Since the environment can't support unlimited population growth, not all individuals get to reproduce to their full potential. 5  There is heredity. 6  The surviving brown ...
The mechanism b â¦ y which organisms evolve is natural selection. Survival of the fittest explains how natural selection works.  Answer = Natural Selection The process of natural selection, of course.