I think the respiratory system and circulatory system
Well the insects eat the plant and the small animals eat the insects and so on.if the insects die the food chain is broken.
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
Answer:
A
Explanation:
The top answer is correct, over time it has become weaker.