Jimmy and Joanna were walking in their backyard and noticed a mushroom growing on the outside of a dead tree. Jimmy claimed that the mushroom was a plant, but Joanna said that it was not a plant, but a fungus. In this case, what evidence BEST supports Joanna's claim?

The mushroom was a producer.

The mushroom was a autotroph.

The mushroom was a parasite.

The mushroom was a heterotroph.