Some special species of molds can grow on other models. These are consuming the energy from the other models.
Mold
NO. Mold can grow many wet places
penicillin is the most common mold to grow on bread
That depends on which type of mold since there are many types of molds and different molds grow better under different circumstances.
Oxygen o2
Hypha
Oranges have plenty of carbohydrates in acedic medium, which are quite congenial to the molds to grow
Acellular slime molds
zygomycetes
Dead logs or fallen trees.
Molds usually get their nutrients from where they grow and live. They can easily have their necessary foods from there and can grow more in number.