A scientist observed a fungus and recorded what she saw:• orange in color• found on the surface of a leaf• tightly arranged hyphae• contains cell walls

Rust is a fungus that can appear orange and grow on leaf surfaces. The tightly arranged hyphae are the key clue distinguishing rust from yeast, which is usually a single-celled fungus rather than a fungus with hyphae. Although both rust and yeast have cell walls, that clue alone does not identify the fungus as rust.

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