Water and salts are both lost from the human body in

Analyze the question: It asks which excretory routes remove both water and salts from the body.

Concept: Different excretory organs remove different substances:

• Lungs (breath): remove carbon dioxide and water vapour. They do not remove salts.
• Skin (sweat): removes water, salts (mainly sodium chloride), and a little urea.
• Kidneys (urine): remove water, salts, urea, and other soluble wastes.

Step-by-step solution:

1. Check breath: it carries water vapour and CO₂ only, with no salts. So any option containing breath (A, B, C) cannot be right, because the question says both water and salts must be lost.
2. Check sweat: it contains water and salts, so it qualifies.
3. Check urine: it contains water and salts, so it qualifies.
4. The only option that combines these two routes is sweat and urine.

**Answer: D. sweat and urine.

Tip: Remember that the lungs lose water but not salts. When a question says "water and salts", look for the routes that deal with dissolved substances, which are the skin and kidneys. If you see "breath" in an option, be suspicious.