Which of the following substances is an element? (1 point)

insulin

O protein

O hydrogen

O salt

hydrogen

Hydrogen is an element.

To determine which of the substances is an element, we need to understand what an element is. An element is a substance that cannot be broken down into simpler substances by chemical means. It consists of only one type of atom.

Let's analyze each substance given:

1. Insulin: Insulin is not an element. It is a protein hormone produced in the pancreas that helps regulate blood sugar levels.

2. Protein: Protein is not an element either. It is a complex biological molecule composed of amino acids.

3. Hydrogen: Hydrogen is an element. It is the lightest element on the periodic table and commonly exists as a diatomic molecule (Hâ‚‚).

4. Salt: Salt is not an element. It is a compound composed of sodium (Na) and chlorine (Cl), which are both elements.

Therefore, the substance that is an element is hydrogen.