In deep-sea diving, divers use a mixture of gases consisting of oxygen and

Answer: Option D

Question: Deep-sea divers breathe a special mix of gases to stay safe underwater. Oxygen is part of the mix, but what other gas is commonly added?

Explanation: Divers need to breathe underwater, just like we do on land. Oxygen is essential for life, but breathing pure oxygen at high pressure (like deep underwater) can be dangerous.

That's why another gas is added to dilute the oxygen. Helium is the most common choice because it is:

1. Lightweight: This makes it easier to breathe at depth.

2. Inert: It doesn't react with the body or other gases.

3. Safe at high pressure: Unlike some other gases, helium doesn't cause problems when breathed under pressure at great depths.

Therefore, the correct answer is D: Helium.