In what type of solution is a contractile vacuole useful? (hypertonic/hypotonic/isotonic)
also, why wouldn't it be in the other two solutions?

Place the steps tor the formation of the enzyme pepsinogen in correct order

Connection compare and contrast genetic engineering to the process of natural selection. select all statements that are true.

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.