Answer:
A. Both freezing and melting are physical changes.
Explanation:
Even if you were to freeze water, the molecules are still water molecules, and vise versa with melting it.
D. layer B is younger than layer G.
Answer:
Enzymes.
Explanation:
That would be enzymes. They increase the rate of chemical reactions in cells.
H20. 2 of hydrogen and oxygen
Reduction involves the either the addition of hydrogen and removal of oxygen.
<h3>What is reduction?</h3>
Reduction involves the removal of oxygen.
This implies there is a loss of oxygen in reduction.
This can be represented in the extraction of iron from it ores.
Fe₂O₃ + 3CO → 2Fe + 3CO₂
Reduction is also the addition of hydrogen. This implies it is the gain of hydrogen.
For example
CH₃CHO → CH₃CH₂OH
learn more on reduction here: brainly.com/question/9485345
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