<h2>Answer:</h2>
Compound. Option A is correct
<h2>Explanations:</h2>
When two or more different elements combines, a compound is formed. For instance, if carbon and oxygen combines, carbondioxide is formed according to the equation;

From the reaction, carbon and oxygen are the elements while carbondioxide is the compound. Hence we can conclude that a pure substance formed when two or more different elements combine called compound.
<span>Heavy metals like mercury enter waterways by industrial dumping and poor regulatioin of effluent, and they also enter soil through a similar manner, in which waste is disposed of imporperly. Another source of heavy metals are the gases leaving industry carrying these metals. The metals fall as a solid on to soil and water ways. Therefore, the answer is D.</span>
Answer:
The answer to your question is: C. The specific latent heat of fusion
Explanation:
A. The specific latent heat of vaporization Specific latent heat of vaporization indicates the transition from liquid to vapor, but we are not looking for this definition. This answer is wrong.
B. The specific heat
indicates the amount of heat needed to increase the temperature of water 1°C, so this answer is wrong.
C. The specific latent heat of fusion
. This heat indicate the transition from solid ie to liquid, so this is the right answer.
D. The internal energy measures the energy of the molecules of a substance, so this answer is wrong.