Final answer:
Fungi were once classified as plants, but scientists observed a key characteristic that required reclassification. The cell walls of fungi are made of chitin instead of cellulose, and fungi absorb nutrients from other organisms.
Step-by-step explanation:
- Fungi were once classified as plants due to their similarities with plants such as immobility, having cell walls, and growing in soil.
- However, scientists observed a key characteristic that required reclassification: the cell walls of fungi are made of chitin instead of cellulose, which is found in plant cell walls.
- Additionally, fungi absorb nutrients from other organisms, while plants can make their own food through photosynthesis.