In order to explain the mass extinction of life on earth 65 million years ago, the expert geologists have proposed several [ Select ] hypotheses hypothetically hypothesis hypotheticals . One of them is the idea that a catastrophic collapse of the global food chain preceded widespread extinction. Another [ Select ] possible opportunity possibility problem is that a massive volcanic eruption blocked the sun and cooled the earth, whereby plant growth diminished and a chain reaction of deaths followed. A final hypothesis, which has some [ Select ] evidential evidents evidently evidence to support it, is that a meteorite from space crashed into the planet and the impact [ Select ] caused was due to subsequently resulted from a cooling effect which [ Select ] caused resulted led impacted to a chain reaction of deaths.多重下拉选择题