How does abrasion shape a shoreline?
rock fragments tumble in the water, wearing away material that is softer than they are.
wind picks up sand and blows it along the shoreline, changing the shape of the beach.
waves force air into cracks in the rock, breaking them apart.
currents flow parallel to the shore, moving large amounts of sediment.

Iron reacts with oxygen to produce iron oxide (rust). this reaction is represented in an equation as 4fe + xo2 → 2fe2o3. identify the value of x that will balance the equation.

Which of the following are false concerning microbes? a. microbes generate oxygen through photosynthesis. b. the primary role of microbes on the planet involves causing disease in animals and humans. c. microbes produce vitamins in the intestines. d. microbes play a role in breaking down waste and decomposing dead organisms.

Read the following scenario to answer the following question. over the past 60 years, many amphibian species have experienced significant population declines, and some species have become extinct. scientists suspected that local human activities such as the destruction of wetlands, regional pollution, and deforestation were the main reasons for these losses. however, research over the past 20 years reveals significant amphibian population declines in protected areas of the world, such as nature preserves and parks. these global declines suggest widespread problems including increased ultraviolet radiation, acid rain, and disease. in switzerland, for example, 14 of the 20 native amphibian species are threatened with extinction. when most populations of a wide-ranging amphibian species are lost and the few remaining populations are widely separated, we expect to see that a. the founder effect becomes increasingly important b. microevolution no longer occurs c. gene flow between populations is reduced d. artificial selection becomes a greater factor in microevolution