The body is a bunch of lever arms and hinges. take the forearm and biceps for example. the biceps tendon is attached approximately 5cm, away from the elbow (this is so close to the hinge we can approximate the force as directly upward). if a person has a forearm length of .4m and a mass of 5.5kg, and they are holding a 10kg dumbbell in their hand, what is the tension in the tendon to keep the arm at rest?

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.

multiple allele inheritance is traits controlled by more than 2 alleles (ex: pigeons having 3 alleles of one gene govern their feather color).