Logical Reasoning

PT142 · S2 · Q10 In a vast ocean region

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In a vast ocean region, phosphorus levels have doubled in the past few decades due to agricultural runoff pouring out of a large river nearby.

Given

In a vast ocean region, AR -causes→ ↑PH phosphorus levels have doubled in the past few decades due to agricultural runoff pouring out of a large river nearby.

The phosphorus stimulates ↑PH -causes→ ↑PL the growth of plankton near the ocean surface.

Decaying plankton fall to the ↑PL -causes→ ↓O ocean floor, where bacteria devour them, consuming oxygen in the process.

Due to the resulting oxygen ↓O -causes→ ↓F depletion, few fish can survive in this region.

10.

Which one of the following can be properly inferred from the information above?

  1. Correct

    The agricultural runoff pouring out

    Why this is right

    The follows from the first two premises. In a vast ocean region, AR -causes? ?PH phosphorus levels have doubled in the past few decades due to agricultural runoff pouring out of a large river nearby. The phosphorus stimulates ?PH -causes? ?PL the growth of plankton near the ocean surface. So agricultural runoff AR -causes? ?PL contributes to the growth of plankton.

    Skill tested: Must be True · how this choice captures the argument's function is the move to repeat next time.

    82% picked this

  2. Before phosphorus levels doubled in

    Negation

    This negates the ~?PH -causes? ~?PL -causes? causal chain. ~?O -causes? ~?F

    9% picked this

  3. If agricultural runoff ceased pouring

    Unsupported Relationship

    The bacteria that devour decaying plankton are not influenced by the causal chain.

    2% picked this

  4. The quantity of agricultural runoff

    Unsupported Comparison

    Phosphorus levels have doubled in the past few decades, but that does not mean the quantity of agricultural runoff doubled as well. The phosphorus could be a small portion of agricultural runoff in general.

    1% picked this

  5. The amount of oxygen in

    Too Strong

    While phosphorus contributes to the depletion of oxygen, the relationship does not need to be proportional. There could be threshold limits that trigger certain reactions making the relationship less consistent than is implied by the phrase, “inversely proportional.”

    7% picked this

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