Answer: a. weathering breaks rocks into minerals and plants die and decay.
The process of soil formation is called as pedogenesis. This process initiates with the weathering of rocks. Weathering is a process in which the rock is broken down into smaller soil particles. Wind, water and chemicals are potent weathering agents. The fine grains of soil are mixed with the organic matter. The organic matter produces as a result of dead animal and plant waste being decayed by the microorganisms in the soil. The organic matter increases the fertility of the soil.
Therefore,a. weathering breaks rocks into minerals and plants die and decay must occur to form soil.
