What kind of system is generally composed of a fluid system to move the heat from the collector to its point of usage and a reservoir to stock the heat for future use?
A.
nuclear power
B.
coal burning
C.
electrical power
D.
solar heating

D

Explanation: Heating systems are generally composed of a fluid system. This system moves heat to it's point of usage   Hope this helps :)

i believe it is "they are not used up by reactions" as the answer to your question, text me back if this is correct because i just learned this.

the water is warmed up by the sun and then it evaporates into the atmosphere. the sunlight warms the water by its heat. water is then cooled down and condensation takes place. the water then finally returns back to the earth by the process of precipitation in the form of rain or ice.

explanation: