A cell with a predominance of rough endoplasmic reticulum

Asquirrel population lives in an area. over many years, a river in that area grows wider and stronger, eventually forming a canyon. the squirrel populations on the two sides of the canyon can no longer mate with each other and ultimately form distinct species. this is an example of

Read the scenario below and answer the question that follows. hallie is reading a novel in the library when susan, her best friend, slumps down in a chair next to her. susan doesn't say anything, but hallie knows that susan is upset because she is slumping in her seat and rolling her eyes. a psychologist would explain that hallie is interpreting her friend's emotion based on a. the behavioral component of emotion b. her friend's ability to regulate emotion c. the verbal component of emotion d. the physiological component of emotion select the best answer from the choices provided a b c d

Why has two different alleles for the same trait?