1. Which layer is the oldest? Which layer is the youngest? How do you know? 2. What are some characteristics of the organisms in layers 1-6?
3. What are some characteristics of the organisms in layers 7-12?
4. Develop a theory as to how the organisms in this area changed over time.

Astudent poured a solution of bromothymol blue indicator into three test tubes. then he placed an aquatic plant in two of the test tubes, as shown below. he placed a stopper on each test tube and placed them all in the dark for 24 hours. bromothymol blue turns from blue to yellow in the presence of co2

14) whenever diploid populations are in hardy-weinberg equilibrium at a particular locus a) the allele's frequency should not change from one generation to the next, but its representation in homozygous and heterozygous genotypes may change. b) natural selection, gene flow, and genetic drift are acting equally to change an allele's frequency. c) this means that, at this locus, two alleles are present in equal proportions. d) the population itself is not evolving, but individuals within the population may be evolving.

In order for you to hold your breath, your nervous system must send messages to your a. respiratory system b. digestive system c. heart in your cardiovascular system d. check in your muscular system