I believe that it is all of the above.
"A Scientific Hypothesis Must Be "Falsifiable". A scientific hypothesis must be testable, but there is a much stronger requirement that a testable hypothesis must meet before it can really be considered scientific."
I hope this helped, have a nice day!
One possible answer could be that a chemical reaction has occurred.
For the first one the answer is B. and the second one is D.
Answer:
B.Convection
the movement caused within a fluid by the tendency of hotter and therefore less dense material to rise, and colder, denser material to sink under the influence of gravity, which consequently results in transfer of heat.