Question

choose the right answer.
2. Which of the following is a chemical reaction brought about by heat?
a) Combustion of methane
b) Decomposition of water
c) Rusting of iron
d) Sublimation of dry ice
3. Which of the following is a chemical change?
a) Dissolving of sugar
b) Sublimation of iodine
c) Electrolysis of water
d) Boiling of water
4. Burning of fossil fuel produces:
a) Oxygen
b) Helium
c) Carbon dioxide
d) Ozone​

Answer 1

Answer:

in first option a is correct