A. A pure chemical substance consisting of one type of atom
Answer:
You may be referring to the gas that makes up 21% of the earth's atmosphere, which is oxygen.
Explanation:
According to NASA, the gases in Earth's atmosphere include:
Nitrogen — 78 percent
Oxygen — 21 percent
Argon — 0.93 percent
Carbon dioxide — 0.04 percent
(Trace amounts of neon, helium, methane, krypton and hydrogen, as well as water vapor)
Answer: Correct options are as follows.
- salt is not chemically bonded to water.
- salt and water retain their own chemical properties.
Explanation:
When salt is dissolved in water then it means that it is a physical change as salt has completely dissociated into ions but they are not chemically combined to the water molecules.
As a result, both salt and water will retain their chemical properties.
For example, NaCl when dissolved in water will dissociate as follows.

Only the particles of salt have evenly distributed in water.
And, when a components of a salt chemically combine with another substance then it will form a new compound.
Therefore, we can conclude that salt dissolved in water is a solution, therefore:
- salt is not chemically bonded to water.
- salt and water retain their own chemical properties.
The answer is c because of going left to right