James ussher used to determine the earth's age to be about 5,000 years old.

Which organelle breaks down sugar molecules that supply energy to the cell ?

When ash and dust begin to settle on the ground, they eventually become compacted by

Which of the following must be true for a fossil organism to be useful as an index fossil? a. the fossil organism must be widespread geographically. b. the fossil organism must be abundant. c. the fossil organism must be limited to a short span of geologic time. d. all of the above.