Like any living thing, mold needs food to survive. Your home presents many building materials that mold can grow on.
Wood lumber - Framing, joists, cabinets, etc.
Drywall - Paper and paint on the surface
Fabric - Furniture, curtains, clothes, etc.
Paint - Painted block walls support mold growth
Non-organic materials may have mold growth on accumulated dirt on the surface. This includes porcelain, rock, and metal surfaces.