What determines the steepness of a volcano? A. how hot the lava is B. how hot the magma is C. what the volcano is made of D. when the volcano last erupted

Which statements explains what the fossil records indicates? check all that apply. a) earth is 4.5 billion years old b) many organisms have become extinct c) mammals have always existed on earth d) mass extinctions have occurred several times on earth e) the amount of water on earth has decreased over time?