¹⁴C/¹²C -How Have Scientists Used Isotopic Analysis to Determine That the That

question 119

Multiple Choice

¹⁴C/¹²C
-How have scientists used isotopic analysis to determine that the rise of atmospheric CO 2 is mostly from the burning of fossil fuels?

• A)¹⁴C concentrations are much higher in urban areas than in rural areas,indicating fossil fuels must have a higher ¹⁴C/¹²C ratio than carbon from other sources.
• B)The decrease in ratios of atmospheric ¹³C and ¹⁴C to ¹²C indicates that the source is fossil fuel carbon.
• C)Both coal and oil contain a high proportion of ¹⁴C.By analyzing ¹⁴C/¹²C ratios,scientists have been able to determine the source based on this fact.
• D)Since ¹⁴C is an unstable isotope,scientists have dated the atmospheric carbon to the period since the Industrial Revolution.

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Definitions:

Pharynx

Throat; opens to airways and digestive tract.

Vocal Cords

The vocal cords are folds of tissue in the throat that vibrate and produce sound when air is expelled from the lungs, playing a crucial role in speaking, singing, and making other sounds.

Ligaments

Bands of tough, elastic connective tissue that connect bones together and provide support to joints.

Spiracle

An external respiratory opening in some animals, particularly insects, spiders, and some fish.