If it is the fill in the blanks.The answer is The circles,or orbits,for electrons are called energy levels.
Answer:
I think it's
A <u>mass </u>extinction occurs when many species go extinct in a relatively short period of time.
Explanation:
Mass extinction is usually defined as a loss of about three-quarters of all species in existence across the entire Earth over a “short” geological period of time. Hence, I think the answer is correct.
They lack rhyme scheme and rhythm, but they are still an artistic expression. hope this gelped! :))