Microscopic life in the soil can play many roles, both positive and negative. Which of the following combinations of soil life would usually be the best choice to ensure long-term sustainable agriculture? all broad classes of microbiota in balance nematodes and symbiotic bacteria microscopic non-animal life, plus earthworms sterile soil free of nematodes

Symbiotic bacteria plus earthworms.

Explanation:

Symbiotic bacteria is a type of bacteria which in which a bacteria lives in association with other organisms and gain benefits from one another. The nitrogen fixing bacteria lives in the roots of the leguminous plants which fixes nitrogen for the plant and in return, the plant provides food. earthworms increased the availability of nutrients, better drainage, and aeration of the soil which is very necessary for the plant growth.

the abdomen (less formally called the belly, stomach, tummy or midriff) constitutes the part of the body between the thorax (chest) and pelvis, in humans and in other vertebrates. the region occupied by the abdomen is termed the abdominal cavity. the stomach secretes acid and enzymes that digest food. ridges of muscle tissue called rugae line the stomach. the stomach muscles contract periodically, churning food to enhance digestion. the pyloric sphincter is a muscular valve that opens to allow food to pass from the stomach to the small intestine.