Answer Help: PT1.S3.Q11

Ninaaazy

If someone has done this question about water vapor and oceans and got it correct: can you please explain to me? I am not understanding the correlation between precipitation and the concentration of oxygen in seawater. I chose A originally if someone can also tell my why thats wrong. Thank you guys!! Appreciate any help

ledkarly

This is a most strongly supported question, so you are trying to find an AC that is basically said in the stimulus. Something that you know its true.

water vapour evaporated from the ocean contains a greater proportion of oxygen 16 and a smaller proportion of the heavier oxygen 18 than does seawater. aka water vapour contains more oxygen 16 but less oxygen 18 than seawater (complicated wording), this is basically saying that in seawater there is less oxygen 16 and MORE oxygen 18 than in water vapour - which is what AC B says, and that is why its correct.

Why AC's are incorrect.

A - we dont know this. the stimulus only talked about water vapour and seawater, not the vapour from the seawater. we cant make any assumptions

C. We dont know this either from the stimulus - the stimulus doesn't talk about interglacial periods.

D. same, the stimulus doesn't talk about this either.

E. same, the stimulus doesn't talk about this either.

Remember, the right answer choice MUST come from the stimulus. you cannot assume anything.

Hopefully this helps!

Ninaaazy

Hi thank you for your response with your explanation it makes sense but it doesn't say that there is a higher % of Oxygen 18, but INCREASED. So I am not understanding how the ocean was affected by sea water that did not go back into the ocean.