In order for a physical barrier to be effective in preventing infection, the barrier must . A. prevent the substance from entering the body, trap the substance when it first enters the body, or flush the substance out of the body B. destroy the substance before it enters the body, prevent the substance from reproducing, or flush the substance out of the body C. trap the substance in t

a

Explanation:

the fossil record provides evidence of a common ancestor to many species.

glacial erosion, the picking up and movement of earth beneath a glacier, is also referred to as plucking. erosion and transportation of individual pieces of bedrock, especially large "joint block occur as a result of this glacial erosion. plucking is type of erosion in which rocks become frozen into the bottom and sides of the glacier.as the glacier moves downhill it 'plucks' the rocks frozen into the glacier from the ground.