Lichen can be used as industrial pollution indicator because:

They cannot grow in polluted areas

The correct answer is Option (2) → They cannot grow in polluted areas

Lichens can be used as an indicator of industrial pollution. Lichens are sensitive to air quality, particularly to sulfur dioxide and other pollutants. In areas with high pollution, lichens either die or fail to grow, while in clean environments, they thrive. This makes them effective bioindicators for detecting pollution levels in the atmosphere.

Lichens absorb nutrients directly from the air, so they are greatly affected by air quality, making them reliable bioindicators of pollution levels.