gmatmachoman wrote:Plankton generally thrive in areas of the ocean with sufficient concentrations of certain
nitrogen compounds near the surface, where plankton live. Nevertheless, some areas,
though rich in these nitrogen compounds, have few plankton. These areas have
particularly low concentrations of iron, and oceanographers hypothesize that this shortage
of iron prevents plankton from thriving. However, an experimental release of iron
compounds into one such area failed to produce a thriving plankton population, even
though local iron concentrations increased immediately.

Which of the following, if true, argues most strongly against concluding, on the basis of
the information above, that the oceanographers' hypothesis is false?


Question asks us to find the answer that suggests oceangrapher's hypothesis is NOT FALSE. This means 4 answer choices will conclude that Oceanographer's hypothesis is FALSE and 1 answer choice will support his claim. Lets see which one does that for us :

A. Not all of the nitrogen compounds that are sometimes found in relatively high concentrations in the oceans are nutrients for plankton.
Incorrect : This is irrelevant to the oceanographer's hypothesis that shortage of iron prevents plankton from thriving. Hence this answer choice is ruled out.

B. Certain areas of the ocean support an abundance of plankton despite having particularly low concentrations of iron.
Incorrect : This implied that oceanographer's hypothesis is false. Eliminated.

C. The release of the iron compounds did not increase the supply of nitrogen compounds in the area.
Incorrect : It is not the deficiency of nitrogen compounds that is the issue here. Eliminated.

D. A few days after the iron compounds were released, ocean currents displaced the iron-rich water from the surface.
Correct : This supports the oceanographer's hypothesis by stating that iron-rich water was displaced from the surface after two days and the planktons dint get a chance to thrive in iron rich water.

E. The iron compounds released into the area occur naturally in areas of the ocean where plankton thrive.
Incorrect : Natural or artificial occurrence of iron compounds is not an issue here. Eliminated.

ssgmatter wrote:I am still not clear on A.......Any takers???

Thanks!

ssgmatter wrote:I am still not clear on A.......Any takers???

Thanks!

kevincanspain wrote:

ssgmatter wrote:I am still not clear on A.......Any takers???

Thanks!

What is the oceanographers' hypothesis?

gmatmachoman wrote:Plankton generally thrive in areas of the ocean with sufficient concentrations of certain
nitrogen compounds near the surface, where plankton live. Nevertheless, some areas,
though rich in these nitrogen compounds, have few plankton. These areas have
particularly low concentrations of iron, and oceanographers hypothesize that this shortage
of iron prevents plankton from thriving. However, an experimental release of iron
compounds into one such area failed to produce a thriving plankton population, even
though local iron concentrations increased immediately.

Which of the following, if true, argues most strongly against concluding, on the basis of
the information above, that the oceanographers' hypothesis is false?

A. Not all of the nitrogen compounds that are sometimes found in relatively high
concentrations in the oceans are nutrients for plankton.

B. Certain areas of the ocean support an abundance of plankton despite having
particularly low concentrations of iron.

C. The release of the iron compounds did not increase the supply of nitrogen
compounds in the area.

D. A few days after the iron compounds were released, ocean currents displaced the
iron-rich water from the surface.

E. The iron compounds released into the area occur naturally in areas of the ocean
where plankton thrive.