What soil horizon is the most important for the growth of plants (agriculture) ?

Explanation:

The O horizon is typically at the top of the soil structure and is made up of mostly organic matter. This organic matter is vital to the growth of crops and other plants because it holds nutrients such as carbon, phosphorus, nitrogen and sulfur.

carbohydrates are the body's preferred source of energy.

you are the source of the heat energy. you can minimize the heat energy by selecting the appropriate clothes to wear.