Answer:
B
Explanation:
Proteins are made up of smaller building blocks called amino acid.
Label O is organic material, label A is topsoil, label B is subsoil and label C is weathered rock. They represent different soil layers.
<h3>Soil layers</h3>
Soli layers, also called horizons, refer to the different layers observed on the ground.
The topsoil is a layer of soil composed of a mixture of sand, silt, clay and organic material referred to as humus.
Weathering rocks refer to the dissolved rocks and/or minerals on the Earth's surface.
Subsoil refers to the layer under the topsoil on the surface of the ground.
Learn more about soil layers here:
brainly.com/question/1933157
