Earth's internal heat comes from which of the following? select all that apply.
a. volcanoes
b. convection cells
c. radioactive elements
d. leftover heat from earth's formation

Write a 150-word essay describing the effect of people's activities on the environment in the region.

Witch one is it soo it the the question b. a,b, c,d

If we represent the solar system on a scale that allows us to walk from the sun to pluto in a few minutes, then a) the planets are microscopic and the stars are millions of miles away. b) the planets are the size of basketballs and the nearest stars are a few miles away. c) the planets are marble size or smaller and the nearest stars are thousands of miles away.