Weegy: The more sensative plants and animals would be unable to live in the polluted river. More robust plants and animals might be able to withstand higher levels of pollution so they could live and even be more successful in the polluted river. [ This is because the tougher plants and animals would be able to fill in where the weaker or more sensative plants and animals got killed off. ] (More)

Weegy: Tectonic plates are composed of the crust and upper mantle rock which is lighter than the more dense mantle. Rising and falling convection currents in the mantle cause imperceptibly slow movements in the plates (on the rate of fingernail growth). [ The source of the heat driving the convection currents comes from residual heat from the Earth's formative processes, pressure from gravity, and from radioactive decay of elements. Convection currents inside Earth provide the mechanism for plate motion. ] User: what are the main ideas of the big bang theory? Weegy: One of the main ideas is that when the universe started out it was a hot clump of matter. then it exloded into what we have today. since the explotion we are still driffting outwards filling all of space. (More)