Listen to a conversation between two students.
W:I think you would have enjoyed my geology class this morning.
M:Don't betbeg on it, I've never caredhear much about rocks.
W:But you do care about dinosaurs I recall and today we discuss the geological evidence about what maymakes have killed off the dinosaurs at least here in North America.
M:Oh, sure, they got hit by a comet or something, I think.
W:Well, yeah, about 60 million years ago, a huge comet did crash into the earth down in Mexico and it plowedproduced out as an enormous crater over a hundred miles acrossa clock.
M:And that's what why deathdoes the dinosaurs, right?
W:Well, it was not exactly the impact itself but what happened right afterward.
M:You see researchers figured out from the shape of the crater
that's the comet must be coming in pretty low across Atlantic and so right after the impact a huge cloud of fire river? must swept clear across the north America, all in just a few minutes. And that what probably kill off not just the dinosaurs, but a lot of different species of plants and animals.
M:Amazing.
W:Yeah, and even 2000 miles from the impact, plants would have been burst in the flames.
M:And the fire that intense mustmostly destroy just about everything.
W:Well, above ground anyway.
M:Above ground? Say, I wonder if it that to explain why the dinosaurs were all disappeared but other animals like maybe small mammals living underground managed to survive.
W:Make sense, anyhow later on the tons of dusts that thrown away out into the atmosphere may have caused some global climate changes, so eventually the comet probably affected the plants and animals species all around the world but nowhere as much as the north America.