The subatomic particle that gives off visible light is electrons
None, it’s solar radiation
B is remaining the constant speed for 4 mins
Answer:

Explanation:
I am assuming that we have to balance this equation. On the left side, we have one Fe, 2 H, 2 Cl, and 1 S. On the right side, we have 1 Fe, 1 H, 1 Cl, and 1 S. Adding a 2 as a coefficient in front of the HCl on the right side will make 2 H and 2 Cl instead, balancing the overall equation.
He will most likely find that the sand has sunken to the bottom because the molecules in sand are to powerful to break apart and disslove.