15.What is one problem that must be overcome before nuclear fusion reactions that produce energy on our planet are a reality? a. Scientists must determine how to control the reaction
b. A company must first apply for a patent
c. Cars have to be redesigned
d. There is not enough open space available in the United States

the dependant variable is spilled water

the independent is the heat

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.

i think slash and