It can be a compound or a single element. An element is a pure substance that cannot be separated into simpler substances by chemical or physical means. There are about 117 elements, butcarbon, hydrogen, nitrogen and oxygen are only a few that make up the largest portion of Earth.
I would say d.
Answer:
A. Whatever is in the water, it moves. Even if a block is placed in there, it would move by sinking to the bottom. If a plastic bag was placed in there, it wouldn't sink but move a little.
The three group 4 elements that occur naturally are titanium, zirconium, and hafnium. The first three members of the group share similar properties; all three are hard refractory metals under standard conditions.