Many observations provide a history that one may be able to surmise theories from.
Answer:
i have the same question. let me know what's the answer pls! I think it's d but im
not sure
Explanation:
So, first of all let me explain the process of hydration to you.
The water causes the hardening of concrete through a process called hydration. Hydration is a chemical reaction in which the major compounds in cement form chemical bonds with water molecules and become hydrates or hydration products.
Considering this information, the answer is D.
The answer is d. temperature differences in the mantle