Answer:
<em>D. A combustion reaction</em>
Explanation:
That is called condensation
I believe that it is a chemical change.
Answer:
is an explanation of an aspect of the natural world that can be repeatedly tested and verified in accordance with the scientific method, using accepted protocols of observation, measurement, and evaluation of results
For a closed system, you need two things:
1) a conservation of mass within the boundaries of the system
2) the ability to freely exchange energy to & from the "closed" system with a surrounding external system
So, the answer is <u><em>never</em></u>, since your defining the "system" as the water within the bathtub, and an open bathtub is exposed to evaporation, which is not conserving mass within the defined "system".
