Fresh milk has several parts that a farmer can separate and sell. A farmer removes the top layer of fat from fresh milk. What property does the farmer use to separate the fat from the rest of the milk? A. density
B. Magnetism
C. Boiling Point
D. Electrical Conductivity

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.