Describe the relationship between poverty and health?

Which of the following statements is true about the relationship between genetic variation and natural selection? a. genetic variation must be present in a population before natural selection can act on it. b. genetic variation arises in a population as a result of natural selection. c. natural selection can act on a population whether there is genetic variation within the population or not. d. after natural selection acts on a population, the amount of genetic variation in the population always increases.

Which spheres are involved when sedimentary rocks formed from parts of seashells at the bottom of the ocean? a.) biosphere, atmosphere, geosphereb.) geosphere, hydrosphere, biosphere c.) geosphere, exosphere, hydrosphered.) hydrosphere, biosphere, atmosphere

One reason scientists are trying to develop fuel sources from corn and sugar is because these sources are renewable fossil fuels are being depleted these crops can be widely grown all of the above