Consider the four spheres. as illustrated by the diagram, we would expect spheres a - c to be attracted to sphere d. sphere d has the greatest gravitational force because as represented here, it
a) is the most massive.
b) has a negative charge.
c) is composed of a metal.
d) is on top of the other three.

Are the layers of rock above and below the coal older or younger?

Which of the following is likely not involved in this example of ecological succession? a) the rotting remains of plants add to the fertility of the soil. b)the soil becomes so fertile that eel grass is replaced by other plant species. c) the roots from plants stabilize the sediment, keeping it in place. d) the concentration of salt becomes so high that all plant life is destroyed.

Kudzu vines grow by climbing and wrapping around trees. trees covered by kudzu can die because they are starved of sunlight. what type of relationship exists between the trees and the kudzu growing on them?