Why did sulfur mass-independent fractionation cease at 2.4 Ga? Explain both the event and the mechanism controlling the shift in fractionation.

The best way to account for any errors or contaminated samples when using radioactive dating is focus on a single radioactive pathway.

Explain how C and N isotopes can be used to determine what trophic level an organism exists at.

When water goes through a phase transition from liquid to gas, what O isotope is most favored by the reaction and accumulates in the gas phase.

During embalming, an embalmer observes that the arterial solution is flowing freely but the drainage is poor. They insert angular spring forceps and remove heavy clots. What is the MOST likely location of these clots?

Which of the following is present in all of the vascular system? (Please choose all that apply)

Which of the following could possibly be the probability of an event? CHOOSE ALL THAT APPLY.

If 15 runners are in a race, how many possible ways are there to award 1st, 2nd, and 3rd place trophies?

How many ways can you rearrange the letters in the word?   E X C E L L E N T

Examine the spinner to the right. a.  Is this spinner equally likely?  Answer yes or no.    Answer as a fraction in lowest terms. b.  What is the probability of landing on green in a single spin?  Answer as a fraction in lowest terms. c.  What is the probability of landing on blue or red in a single spin?  Answer as a fraction in lowest terms. d.  If you land on purple on the first spin, what is the probability of landing on purple on the next spin?  Answer as a fraction in lowest terms.