What is the temperature of melting ice? a.) 0 °c b.) less than 0 °c
c.) more than 0 °c d.) there is no way to know for sure without a thermometer

If i am correct the answer should be C because less than the amount would mean the ice has to melt from its ice form back to the original water liquid form.

answer : a model is often used to explain and make things easier to understand when any scientific topic needs to be demonstrated and explained.

as in this case where a scientist wants to use a model to present the results of his detailed scientific investigation. he should do it as it will him to make the audience understand the concept in a much better way. also, it can be changed according to new scientific understandings.