Read the given passage and answer the questions that follow.
We probably owe our existence to a catastrophic cosmic impact. Some 66 million years ago, an unimaginable natural disaster put a permanent end to the dinosaurs. This suddenly opened new, rapid evolutionary possibilities for mammals, ultimately including primates. The rest is history, as the saying goes: If the dinosaurs hadn’t become extinct, Homo sapiens would almost certainly never have walked the earth.
We now know that dinosaurs first appeared on the scene some 230 million years ago, and from just under 200 million years ago were the dominant life form on Earth. They might still have been so today had the cosmos not put a stop to that.
We know from geological research that dinosaurs became extinct 66 million years ago, at the threshold of the Cretaceous and Paleogene periods. These time periods are often defined by the fossils found in ancient rock layers, so it is no coincidence that the disappearance of the horned Triceratops and the dreaded Tyrannosaurus rex coincided with such a geological transition. At the same time, countless other life-forms also disappeared, both on land and in the ocean. In total, three-quarters of all biological species on Earth perished. The term 'mass extinction' is therefore no exaggeration.
Dinosaurs, which had ruled the planet for tens of millions of years, did not see their sudden end coming. But we humans are well aware of the danger, and it would be completely irresponsible of us not to properly assess the risks, and not to think about ways to avert such a fate.