Q23 - A group of scientists studying

[michaeljanati]

I am completely lost on this question!

[ManhattanPrepLSAT1]

No problem. Let's take a look.

Rats in experiment 1
no adrenal gland
+
parathyroid gland
--------------------
calcium decreases sharply


Rats in experiment 2
no adrenal gland
+
no parathyroid gland
--------------------
calcium decreases less sharply


This means that the parathyroid gland is decreasing calcium. Without the parathyroid gland more calcium is present and with the parathyroid gland less calcium is present.

We need an answer choice that reflects this, and so answer choice (A) is the correct choice.

(B) is the opposite of what we want (just in case we got turned around as we sorted things through.
(C) is irrelevant because in both instances the adrenal gland was removed.
(D) would challenge the findings in the first experiment.
(E) is too restricting and wouldn't explain the result.

Does that clear this one up? (A) and (B) were probably the most tempting of the answer choices, (C) could have been tempting if you didn't know what you were looking for when you hit the answer choices, but (D) and (E) should have been throwaways!

[dtangie23]

No problem. Let's take a look.

Rats in experiment 1
no adrenal gland
+
parathyroid gland
--------------------
calcium decreases sharply


Rats in experiment 2
no adrenal gland
+
no parathyroid gland
--------------------
calcium decreases less sharply


This means that the parathyroid gland is decreasing calcium. Without the parathyroid gland more calcium is present and with the parathyroid gland less calcium is present.

We need an answer choice that reflects this, and so answer choice (A) is the correct choice.

(B) is the opposite of what we want (just in case we got turned around as we sorted things through.
(C) is irrelevant because in both instances the adrenal gland was removed.
(D) would challenge the findings in the first experiment.
(E) is too restricting and wouldn't explain the result.

Does that clear this one up? (A) and (B) were probably the most tempting of the answer choices, (C) could have been tempting if you didn't know what you were looking for when you hit the answer choices, but (D) and (E) should have been throwaways!

How can the presence of the parathyroid gland decrease the level of calcium? It says that the parathyroid raises the level of calcium when it falls below normal levels. It also says that the removal, not the presence, results in lower than normal levels of calcium.

[lhermary]

No problem. Let's take a look.

Rats in experiment 1
no adrenal gland
+
parathyroid gland
--------------------
calcium decreases sharply


Rats in experiment 2
no adrenal gland
+
no parathyroid gland
--------------------
calcium decreases less sharply


This means that the parathyroid gland is decreasing calcium. Without the parathyroid gland more calcium is present and with the parathyroid gland less calcium is present.

We need an answer choice that reflects this, and so answer choice (A) is the correct choice.

(B) is the opposite of what we want (just in case we got turned around as we sorted things through.
(C) is irrelevant because in both instances the adrenal gland was removed.
(D) would challenge the findings in the first experiment.
(E) is too restricting and wouldn't explain the result.

Does that clear this one up? (A) and (B) were probably the most tempting of the answer choices, (C) could have been tempting if you didn't know what you were looking for when you hit the answer choices, but (D) and (E) should have been throwaways!

I don't get it

Parathyroid removed - lower levels of calcium
Parathyroid and Adrenal removed - decreasing levels of calcium but at a lesser rate

Therefore, the adrenal gland acts to lower the level of calcium in the blood???

That doesn't make any sense.

[lhermary]

Can anyone answer this?

[timmydoeslsat]

I view this as a resolve the paradox question.

We have experiments going on in this stimulus.

A group of scientists are studying how calcium is metabolized in lab rats.

The scientists performed an experiment in which the parathyroid was removed from the rats. This resulted in the rats having substantially lower than normal levels of calcium.

The scientists made a hypothesis about what was happening here. They formed a hypothesis that the parathyroid was responsible for regulating the level of calcium in the blood when that level falls below normal.

This hypothesis would help to explain why the rats, after having the parathyroid removed, were showing major low levels of calcium. With no parathyroid in the rats, when the calcium fell below normal, this gland is no longer present to raise the level back to normal.

In a later experiment, the scientists removed the parathyroid and the adrenal glands this time.

While one may expect for the major low levels of calcium to be present in these rats due to the parathyroid being removed, it was the case that the levels of calcium were not as low as it was in the first experiment.

This would hint to us that the adrenal gland may be causing this differing result from the first experiment to the second experiment, as this is the only reported difference to us.

Answer choice A fits perfectly.

A) The adrenal gland acts to lower the level of calcium in the blood.

If it were true that adrenal glands act to lower the level of calcium, that would be consistent with what was shown in the first experiment.

In the first experiment, only the parathyroid was removed. This resulted in substantially lower than normal levels of calcium. The fact that the adrenal gland was left in the rats is consistent with this result of having low level of calcium. It is still in the rats and that is how it acts.

In the second experiment, the parathyroid and adrenal glands are removed. So, by removing the adrenal glands as well, it is as if we are removing a weight that further bogs down the calcium level!

That is perhaps why the calcium level did not suffer as sharp of a drop as it did in the first experiment. The "extra weight" of bogging down the calcium levels was removed when the adrenal gland was removed. This allowed the calcium levels not to drop as deep as it did in the first experiment when the adrenal glands still remained.

[Turismo1]

^ thanks for posting that. I ran into that question yesterday and have been scratching my head ever since.

[mark_gg_daniels]

I hated this question so much because I'm a Bio post grad, and none of the answers would be credible scientific hypothesis.

But it taught me an important lesson: Completely ignore the facts and simply focus on the argument, even if all the answers wouldn't be used in the real world.

This was in the LSAT too BTW (which I'm currently prepping for)

[Ibrahim.diallo]

This is a visual that I came up with during review which helped me understand the answer. It's reverse re-engineered but I think it helps you see the argument visually, especially if you are still confused after reading the explanations.

[YiX773]

It's cruel. Little rats didn't do anything wrong.

/PG + AG = Decrease sharply (+++)
/PG + /AG = Decrese much less sharply (+)

then we know

When AG is there, Decrease +++. When no AG, Decrease +.

So AG is responsible for part of the decrease.

[Laura Damone]

Strong reasoning, Yi!