Which of the following is an example of natural erosion?
a.
ice forming in cracks of rocks
b.
acid rain falling on sidewalks
c.
waves washing over rocks on the beach
d.
water washing away soil in an area used by off-road vehicles

Which table best shows the impacts resulting from human activity? impact of human activities human activity impact forest area cleared to construct an airport increase in oxygen level vegetation cleared to construct an oil mine increase in pollution impact of human activities human activity impact forest area cleared to construct an airport increase in sound pollution vegetation cleared to construct a power plant contamination of water impact of human activities human activity impact beehives cleared from urban areas increase in vegetation dams constructed on a river increase in fish population impact of human activities human activity impact beehives cleared from urban areas increase in bird population dams constructed on a river better quality of water

For a comparative or experimental investigation, scientists often make a testable about a scientific question, and then they test it in the investigation. a.control b.hypothesis c.procedure d.system

Archaebacteria use for movement. celia flagella pili cell walls