The correct answer is a model of mountain formation.
Explanation:
A model signifies towards a demonstration of a process, an idea, or a system that is used to illustrate a particular procedure, which cannot be experienced straightforwardly. The models are generally used in science to illustrate various procedures. When one is speaking about an appropriate model to demonstrate an incident, which takes place gradually, the most likely choice from the mentioned options will be a model of mountain formation. This is due to the fact that the procedure of mountain formation takes place very gradually over an extended time duration.
The distance from the equator affects the climate of a place. At the poles, energy from the sun reaches the Earth's surface at lower angles and passes through a thicker layer of atmosphere than at the equator.
Complete digestion of food takes place in the intestine. Various enzymes present in the intestine act on food and digested food gets absorbed. Typhlosole increases the absorption surface of the intestine.13
