Answer:
8)
Potential Explosions
Radiation
Radioactive Waste
9)
1st option
10)
Nuclear Fission is not a good source of energy. This is by reason of only 0.7% of the uranium being captured. This is small even if one doesn't mention that only 40% of that 0.7% is converted into usable energy. There are also chances that the power plant could explode during conversion. All of this evidence points to the fact that Nuclear Fission and Nuclear Energy themselves should not be relied on.
11)
Sun and Stars
7)
Uranium and Plutonium
Carbon (C) is an element
Carbon Dioxide (CO2) is a compound
Hydrogen (H) is an element
Sodium Chloride (NaCl) is a compound
A good way to tell whether something is a compound or an element, is that in a compound there is a mixture of different elements. Like in Carbon Dioxide, the symbol is CO2. This shows the carbon (C) and oxygen (O) together. I hope i worded that well enough and this helps :)

The answer is...
B. Cooling as the lava runs down the mountain.
Hopefully, this helps you!!

C. They unwinds the two strand of DNA.