()4. Why did the dinosaurs die out? A. Because they killed each other. B. Because an asteroid hit the Earth. C. Because humans killed them.()5. Which of these present-day animals is descended from(源于)dinosaurs? A. Frog. B. Alligator (). C. Hummingbird(蜂 ) 相关知识点: 试...
Around 66 million years ago, at the end of the Cretaceous period,an asteroid struck the Earth, triggering a mass extinction that killed off the dinosaurs and some 75% of all species. Somehow mammals survived, thrived, and became dominant across the planet. What was before dinosaurs? The age...
These data show that a relatively diverse assemblage of dinosaurs survived the end-Cretaceous asteroid-impact extinction event of 65.5 Ma. The San Juan Basin's Paleocene dinosaur fauna is herein named the Alamoan fauna. Magnetic-polarity chronology shows that these survivors lived for about one ...
From then until the dinosaurs died out 65 million years ago, any land animal longer than about 3 feet was an archosaur, says Farmer, while mammal-like synapsid survivors "were teeny little things hiding in cracks. It was not until the die-off of the large dinosaurs 65 million years ago ...
How big was the asteroid that killed the dinosaurs? The asteroid is thought to have beenbetween 10 and 15 kilometres wide, but the velocity of its collision caused the creation of a much larger crater, 150 kilometres in diameter - the second-largest crater on the planet. ...
For the record, let it be known that James A. Corry is a convicted criminal placed in solitary confinement. Confinement in this case stretches as far as the eye can see, because this particular dungeon is on an asteroid nine million miles from the Earth. Now witne...
Pterodactyls are anextinctspecies of winged reptiles (pterosaurs) that lived during the Jurassic period (about 150 million years ago.) Why did flying dinosaurs go extinct? Most bird-like dinosaurs, including 80 known opposite bird taxa, disappear fromthe fossil record after the asteroid strike. ...