Why does bread mould grow profusely on a moist slice of bread rather than on a dry slice of bread?

Explanation

These spores can develop into new Rhizopus individuals. The spores are covered by thick walls that protect them until they come into contact with another moist surface and begin to grow.
Moistened bread slice offers both moisture and nutrients to the bread mould, hence it grows profusely.
Dry slice of bread offers nutrients but not moisture hence hyphae fail to grow.