Final answer:
The relationship between plants and specialized fungi is classified as mutualistic symbiosis, where both organisms benefit each other.
Step-by-step explanation:
The relationship between plants and specialized fungi in which the plant supplies carbon to the fungus and the fungus supplies nutrients to the plant is classified as mutualistic symbiosis. In this type of symbiotic relationship, both organisms benefit from each other. The plant provides the fungus with sugars produced through photosynthesis, while the fungus provides minerals and water to the plant's roots.