Explanation:

- Option 1: Sunlight

Sunlight is an abiotic factor. It is a non-living element that provides energy for plants.

- Option 2: Carbonic substance

This refers to compounds containing carbon, like carbon dioxide. These are non-living, so also abiotic.

- Option 3: Humidity

Humidity is the amount of water vapor in the air. It is a physical, non-living factor, making it abiotic.

- Option 4: Fungi

Fungi are living organisms. As such, they are a biotic component of ecology, interacting with other living things.