(∃X)[Px • (∃Y)(Qy • Y=x)] ⊃ (∃X)(Px • Qx)

question 25

Multiple Choice

(∃x) [Px • (∃y) (Qy • y=x) ] ⊃ (∃x) (Px • Qx)
-Consider assuming '(∃x) [Px • (∃y) (Qy • y=x) ]' for a conditional proof of the above logical truth. Which
Of the following propositions is a legitimate second step in that proof?

• A) (∃y)(Qy • y=x)
• B) Px • (Qx • x=x)
• C) Pg • (∃y)(Qy • y=g)]
• D) Px • (∃y)(Qy • y=x)
• E) Assume '(∃x)(Px • Qx)' for a nested indirect proof.

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Definitions:

Reabsorbed

The process by which substances are taken back into the blood from the filtrate produced in the kidneys.

Concentration Gradient

A variation in the concentration of a substance across a distance; a key factor in diffusion processes.

Loop Of Henle

A section of the nephron in the kidney that concentrates urine and reabsorbs water and ions.

Reabsorption

The process by which the kidneys filter and then absorb back into the blood certain substances or water from the urine.