Psychology

If you teach your dog a trick and then reward him with a treat when he performs the trick, this is an example of learned behavior. Over time, the dog learned that he would be rewarded for following your command.

mechanical

to show the way to food

diffusion

Muscle.

response to stimuli

Antibodies.

The answer is hostility. All human beings are hostile. They like to quarrel with each other. At times they fight with each other. Some times they kill each others, for silly reason like religious misbeliefs. He can not live with out the society. He becomes insane when kept in solitude. He become insane when he lives in society as well. Few types of monkeys also have some what similar pattern of behaviour. But is is not as much pronounced. The nature has chosen wrong species for evolution, probably.

An accessory organ of digestion is one that is involved in the process of digestion but is not actually a part of the digestive tract. An example of this is the tongue.

nerhrons are the smallest functional filtering units of kidneys.

Group Behavior..

Maintenance of homeostasis

internal fertilization