A. Ribozymes are RNA that can self-replicate.
B. DNA does not require enzymes to replicate.
C. RNA stores genetic information on ribozymes.
D. Chains of RNA will form lipid membranes.
12. What is the approximate age of the oldest known fossils?
A. 4.6 billion years
B. 3.5 billion years
C. 3.8 million years
D. 1.8 million years
13. When one organism lives inside the body of another and both benefit, the relationship is called
14. The fossil evidence indicates that anaerobic prokaryotes were
A. the first living organisms.
B. a source of genetic variation.
C. not capable of photosynthesis.
D. always found in colonies.
15. The theory of endosymbiosis states that large prokaryotes took up smaller simple prokaryotes that became
A. the cellular nucleus.
B. complex amino acids.
C. mitochondria and chloroplasts.
D. mitochondria and nuclei.
16. Asexual reproduction produces offspring with
A. half of a single parent's genes.
B. the same genes as the parent.
C. a mix of genes from two parents.
D. lots of genetic variation.
17. Fossils that consist of minerals that have filled in an open mold of an organism are called
B. natural casts.
C. preserved remains.
D. trace fossils.
18. Which of the following characteristics must a good index fossil have?
A. very rare, easy to identify, existed for a brief time, occurs in a local area
B. somewhat rare, hard to identify, existed for a brief time, widespread
C. common, hard to identify, existed for a long time, widespread
D. very common, easy to identify, existed for a brief time, widespread
19. The smallest unit of geologic time is a(n)
20. The bacterium shown in Figure 12.1 may have evolved into a mitochondrion after going through the process of
21. What do scientists estimate as the age of Earth?
A. 100 million years old
B. 4.6 billion years old
C. 10 billion years old
D. 3.8 million years old
22. The Miller-Urey experiment demonstrated that
A. organic molecules first could have come to Earth on a meteorite.
B. iron-sulfide bubbles may have acted as the first cell membranes.
C. liposome membranes containing organic molecules preceded true cells.
D. energy from lightning might have helped create Earth's first organic molecules.
23. During which period did all existing animal phyla develop?
24. Scientists hypothesize that cyanobacteria changed the early Earth by
A. adding oxygen to the atmosphere.
B. developing endosymbiotic relationships.
C. turning into eukaryotic cells.
D. getting energy from organic molecules.
25. During which era did the dinosaur population peak?