Molluscs in Mumbai's intertidal area live at different levels on rocks, sand, and mud. They prefer specific zones with the best conditions for them. Rocky shores have more diverse molluscs than sandy or muddy ones. The mid and lower zones have the most variety. Some areas, like Girgaon chowpatty, have no molluscs in the upper zone due to human activities. Certain molluscs can adapt to different environmental conditions in all three zones.