Three-kingdom Classification System:

In 1866, Emst Hackel solved the first objection and proposed a third kingdom; Protista to accommodate Euglena-like organisms. He also bacteria in the kingdom Protista. In this system, Fungi were still included in the Kingdom Plantae.

Drawbacks of Three-kingdom Classification System:

This system didn’t clarify the difference between Prokaryotes and Eukaryotes. Some Biologists disagreed about the position of Fungi in Kingdom Plantae. Fungi resemble plants in many ways but aren’t Autotrophs. They are a special form of Heterotrophs that get their food by absorption. They do not have cellulose in their cell walls but rather possess chitin.