I would say
a. biological pest control
biological pest control is when other plants or animals are used to control pests. There are no chemicals used only the natural roles of the environment.
Hope this helped!
Plant Roots. The root system of a plant constantly provides the stems and leaves with water and dissolved minerals. In order to accomplish this the roots must grow into new regions of the soil. The growth and metabolism of the plant root system is supported by the process of photosynthesis occurring in the leaves.
A. producer. In their biological process they produce energy. They are very important in the ocean.
Hoped I helped!