The Sudden Appearance of Organisms with Shells and Other Hard

Q6: At the time the earth was formed,the

Q7: The mass extinction of 65 million years

Q8: Most of the history of life on

Q9: The universe<br>A)has always been the same size

Q10: Multicellular organisms first appear<br>A)3.6 billion years ago.<br>B)2

Q12: Photosynthesis is<br>A)a process found only among modern

Q13: Organic compounds on earth first came from<br>A)processes

Q14: The formation of the "supercontinent" of Pangea<br>A)was

Q15: How old is the first evidence of

Q16: The earth was formed about<br>A)1 million years