The rusty crayfish is harmful to native species of crayfish because it clear cuts the bottom of waterways leaving native species without a food supply.

The statement is true. Rusty crayfish can consume and remove large amounts of aquatic plants and other food, damaging habitat and reducing food available to native crayfish. This harmful removal of vegetation is often described as “clear-cutting” the bottom of waterways, so the correct choice is T.

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