Answer:
Troposphere.
Explanation:
Humans live most of their lives in the troposphere atmosphere.
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:
Aa
Explanation:
The dominant gene is purple and usually represented with the capital letter while the recessive gene is white
Answer:
Blood is carried away from the heart by arteries. Blood that is rich in oxygen. Blood that is low in oxygen is returned to the heart by veins. there is more pressure in arteries than in veins.
