27) a 10 kg box is sitting on a shelf 15 feet in the air. how could you increase the potential energy of the box? (check all that apply)
 raise the box to 20 feet.
 lower the box to 10 feet
 increase the mass of the box to 15 kg
 decrease the mass of the box to 5 kg

The eruption of a nearby volcano causes a prairie ecosystem to receive a lot less sunlight. which of these is most likely effect on the ecosystem?

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 three statements represent the benefits of performing experiments using computer simulations?