Answer: More than 99 percent of all organisms that have ever lived on Earth are extinct. As new species evolve to fit ever changing ecological niches, older species fade away. But the rate of extinction is far from constant. At least a handful of times in the last 500 million years, 75 to more than 90 percent of all species on Earth have disappeared in a geological blink of an eye in catastrophes we call mass extinctions.
Though mass extinctions are deadly events, they open up the planet for new forms of life to emerge. The most studied mass extinction, which marked the boundary between the Cretaceous and Paleogene periods about 66 million years ago, killed off the nonavian dinosaurs and made room for mammals and birds to rapidly diversify
Answer:
The reactivity greatens the farther you go down on the periodic table. Lithium will have the weakest reaction, and cesium will have the greatest reaction. Patterns like this are useful to scientists because it shows which elements are the most reactive and which aren't. The farther down and to the left you go within the periodic table, the more reactive the elements become. The farther up and to the right you go, the less reactive they become.
Explanation:
Because they create their own food so they capture sunlinght to produce sugars
I think the answer is evolution.
