An abiotic factor refers to a non-living component of an ecosystem that can affect living organisms. Option 1, mites, and option 3, insects, are both biotic factors as they are living organisms. Option 4, rodents, is also a biotic factor as it refers to living organisms. Therefore, these options are not correct.
Option 2, moisture, is the correct answer. Moisture refers to the amount of water in the environment and is a non-living component of the ecosystem. It can have a significant impact on the distribution and survival of living organisms. For example, organisms in a desert ecosystem may struggle to survive due to low moisture levels, while organisms in a rainforest ecosystem may thrive due to high moisture levels.