Answer:
Rock
Explanation:
Let's calculate the density of each object:
Rock:
Pencil:

Therefore the rock is denser.
Cp stands for specific heat.
You did not include the statements but since magnesium chloride is ionic substance that we know that magnesium and chlorine formed an ionic bond. Therefore your statement most likely will talk about how one magnesium atom gave up 2 electrons while two chlorine atoms took 1 electron. The reaction looks like Mg+2Cl⇒MgCl₂.
I hope this helps. Let me know in the comments if anything is unclear.
Waves with higher frequencies have shorter wavelengths, and lower frequencies have longer wavelengths
The choices can be found elsewhere and as follows:
<span>a. large supply of nutrients.
b. thick layer of mud.
c. lack of insects
d. ability to prevent floods.
</span>
I believe the correct answer is option A. Wetlands provide habitats for many living things because of their sheltered waters and large supply of nutrients. Hope this answers the question.