10. Vestigial structures Are dangerous and should be removed.
Are fully functional structures in a species.
Are usually present, but are no longer functional.
Have been completely eliminated from the species.

Are usually present, but are no longer functional.

Explanation:

Vestigial structures are "evolutionary remnants". They are anatomical features that were once important throughout the organism's evolution, but now have no function. However, they aren't harmful either, so there has been no selective pressure for them to be removed via evolution.

Good examples in humans are the tail bone, wisdom teeth, and the appendix.

compost can be added to topsoil as a:

pesticide