Question

an element found in all proteins but not found in carbohydrates and lipids is

1. carbon
2. hydrogen
3. oxygen
4. nitrogen

Explanation:

Carbohydrates are composed of carbon, hydrogen, and oxygen. Lipids are mainly made up of carbon, hydrogen, and oxygen (though some lipids may have other elements in small amounts in specific cases, but generally). Proteins are composed of carbon, hydrogen, oxygen, and nitrogen (and sometimes sulfur and other elements in some cases). So the element that is in all proteins but not in carbohydrates and lipids (in their basic composition) is nitrogen.

Answer:

1. nitrogen