What is the function of the contractile vacuole?

Aresearcher is studying the science of attractiveness and asks volunteer test subjects to rank what trait they find most attractive in a person what type of variable is the dependent variable in this experiment

Loss of protected health information collected for research should be directly reported to:

How is ribosomal rna useful as a molecular clock? a. a large portion of the dna ring is not vital to structure or function, allowing it to accumulate neutral mutations. b. its rate of mutation increases over time as organisms continue to evolve and differentiate from each other. c. a slow mutation rate makes it useful for determining evolutionary relationships between ancient species. d. it is only found in select organisms, making it easier to compare relationships between species that have it.