The substances that make sweat feel gritty are water ______ and ______.

• A. cohesion; adhesion
• B. lipids; proteins
• C. solvents; gases
• D. solutes; salts

Answer: (D)

Verified step by step guidance

1. Understand the composition of sweat: Sweat is primarily composed of water, but it also contains dissolved substances such as salts and other solutes.
2. Define solutes: Solutes are substances that dissolve in a solvent (in this case, water). Examples include salts, ions, and other small molecules.
3. Explain why sweat feels gritty: The gritty texture of sweat is due to the presence of salts and other solutes that do not completely dissolve or may crystallize on the skin.
4. Eliminate incorrect options: Cohesion and adhesion refer to water's molecular properties, lipids and proteins are not typically found in sweat, and solvents and gases do not explain the gritty texture.
5. Conclude with the correct answer: The substances responsible for the gritty feeling in sweat are solutes and salts, which are dissolved in the water component of sweat.