Scientists have observed that earth's tectonic plates move in predictable directions. what is the cause of this observation? uniform pressure inside earth forces the plates to move uniform temperature inside earth forces the plates to move variations in temperatures inside earth forces the plates to move vibrations in the core forces the plates to move

Its c. Variations in temperatures inside Earth forces the plates to move :)

Answer is: variations in temperatures inside Earth forces the plates to move

Explanation:

Inside the earth, under the crust, we have like a great melted mineral soup at a very high temperature, which increases with depth. Thereby, the upper part is coolest than the deepest one and this generates a movement among the soup, because the coolest magma become heaviest and goes down and the hottest magma goes up creating a cycle called Convection cells that finally force the plates to move.

if the type of the food available changes, then the frequency of beak types will change, because birds with beaks more suited to the available food will be more successful over time.

answer; both surfaces of the membrane are nonpermeable