After studying plate tectonics, Lee became interested in mid-ocean ridges and how rock develops as the tectonic plates spread apart, so he decided to investigate further. Which of the following statements are true about sea-floor spreading? Choose the three statements that apply. A. Young rock forms in layers on the ocean floor as spreading occurs.
B. Magma flows through cracks in Earth's crust and hardens.
C. Continental crust is formed by the ridges as they grow.
D. Mid-ocean ridges are the sources of the spreading.
E. Older rock is farther away from the mid-ocean ridges.

Arrange the following in the correct sequence, from earliest to most recent, in which these plant traits originated. 1. sporophyte dominance, gametophyte independence 2. sporophyte dominance, gametophyte dependence 3. gametophyte dominance, sporophyte dependence a) 1 → 2 → 3 b) 2 → 3 → 1 c) 2 → 1 → 3 d) 3 → 2 → 1 e) 3 → 1 → 2

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. chytridiomycosis is a fungal disease first identified in 1998 as a cause of massive amphibian deaths. in some severely impacted populations, a few individuals have survived, perhaps because of some natural resistance. if these resistant individuals continue to survive and prosper, new resistant populations might emerge. this would be an example of the founder effect artificial selection genetic drift natural selection sexual selection

The united states produces an average of 429 billion pounds of food annually. about 133 billion pounds of that food ends up as waste.the percentage of food that the united states wastes each year is %.