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

Explanation

Wet dump substratum with supply of nutrients is favoured by Rhizopus for spore germination. Spores remain dormant till they come in contact with moist surface. Hence spores of bread mould germinate on moist bread serving as source of moisture and nutrients.
On the other hand, dry bread does not provide moisture needed for spore germination and growth of hyphae.