Answer: A. Microorganisms that live in the soil or on plant roots
B. Water from rain or melted snow
Explanation: Soil is the base for plants to grow. A soil is termed as healthy soil which contains all the biotic and abiotic factors that are essential for the plant growth.
Biotic factors : Biotic factors include all the necessary living organisms that promote plant growth. Biotic factor mainly include bacteria , fungi , protozoa , algae etc.
Microorganisms made Symbiotic relationship with plant. They provide plant essential nutrients and plant provide them shelter.
Abiotic factors : Abiotic factors include non living factors such as air , water , sun light etc.
Water is most important abiotic factor for healthy soil. Water helps plant to transport essential nutrients present in soil through the plant. Water also gives plant stability in the soil.
Melted snow can also be used in place of water.