Match the era on the left with its characteristic on the right.
?
When Earth's atmosphere
formed
Precambrian
2
Ended with a massive
impact
Paleozoic
12
When oxygen-breathing
organisms first thrived
Mesozoic
Cenozoic
Began about 65 million
years ago
SUBNUTI

Using complete sentences, describe the central economic problem facing all humans. why does this require people to make choices? how can this result in opportunity costs?

Which revelation resulted from the observation of the spectrum of different galaxies? a. there were more galaxies whose spectrum was blueshifted b. there were no galaxies whose spectrum was redshifted c. there were more galaxies whose spectrum was redshifted d. there were no galaxies whose spectrum was blueshifted

Explain the reason for having an equator and a prime meridian. how do these two lines us to navigate our world? describe your opinion in at least two to three sentences.