25 A 10 meter by 10 meter plot of land has 25 trees on it. What is the population density of the trees?
A. 0.025 trees/m2
B. 0.25 trees/m2
C. 2.5 trees/m2
D. 25 trees/m2

Drag each tile to the correct box. arrange the layers and faults from oldest to youngest.

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.

What is gene flow? apexa: selection for average traits b: when a population splits in twoc: a mutation becoming more commond: genes moving between two populations