What is the limitation of using rock models?

Models are used to simulate reality and make predictions. The major limitation of models is that they are 'idealizations' or 'simplification' of reality and thus cannot possibly replace reality. A number of assumptions are made during modeling and this causes differences between model and reality.

Explanation:

he is very short, and he can only reach halfway up on the elevator buttons. but on a rainy day, he has his umbrella with him, and he uses it to poke the button at the top.

what statement best describes the difference between the sympathetic and parasympathetic nervous systems?

the sympathetic nervous system prepares the body for intense physical activity and is often referred to as the fight-or-flight response. the parasympathetic nervous system has almost the exact opposite effect and relaxes the body and inhibits or slows many high energy functions.