Most of the History of Life on Earth Has Involved

Q3: Some of the earliest fossils indicate that

Q4: The extinction that wiped out the dinosaurs

Q5: Sexual reproduction probably evolved<br>A)to increase genetic variation.<br>B)to

Q6: At the time the earth was formed,the

Q7: The mass extinction of 65 million years

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

Q11: The sudden appearance of organisms with shells

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

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