Which of the following is NOT an abiotic factor?

The correct answer is based on the definition of abiotic factors, which are the non-living components of an ecosystem that influence living organisms. Sunlight, air, and temperature are all abiotic factors because they are physical and chemical elements of the environment.

Soil organisms, on the other hand, are living entities and fall under the category of biotic factors. These organisms, such as bacteria, fungi, and insects, interact with the soil and play critical roles in nutrient cycling and other ecological processes. Because soil organisms are alive and part of the biological community in an ecosystem, they cannot be classified as abiotic factors. This distinction clearly identifies them as the correct choice for what is not an abiotic factor.