Which is an example of how bacteria help keep the environment clean?
They can reduce oxygen in the air.
They can decompose waste.
They can help develop medicines.
They can slow digestion.

Select the correct answer. which statement applies only to the axial skeleton, not the appendicular skeleton? a. it contains a pivot joint. b. it has muscles attached that work in pairs. c. it contains red bone marrow. d. it possesses fossa for bone articulation. e. it protects the heart and lungs.