Question

1. percent abundance describes: *

a) the charge of an isotope
b) how often an isotope occurs in a sample
c) the weight of an isotope in grams
d) the stability of an isotope

1. the reliability of isotope proxies depends primarily on: *

a) total isotope quantity
b) consistent and predictable fractionation mechanisms
c) radioactive decay rates
d) electron configuration

1. the great oxidation event (goe) significantly impacted: *

a) radioactive isotope decay rates
b) sulfur isotope fractionation patterns
c) carbon - 14 production
d) oxygen isotope ratios

Explanation:

• For question 9: Percent - abundance is a measure of how frequently a particular isotope occurs in a sample compared to other isotopes of the same element.
• For question 10: Isotope proxies rely on consistent and predictable fractionation mechanisms to be reliable. Fractionation is the process by which isotopes are separated based on their mass, and if these mechanisms are consistent, the proxies can be used to infer past environmental or geological conditions.
• For question 11: The Great Oxidation Event (GOE) significantly impacted sulfur isotope fractionation patterns. The increase in oxygen levels during the GOE led to changes in the oxidation - reduction state of the environment, which affected sulfur - cycling processes and thus sulfur isotope fractionation.

Answer:

1. b) How often an isotope occurs in a sample
2. B) Consistent and predictable fractionation mechanisms
3. B) Sulfur isotope fractionation patterns