Hemoglobin, a substance in human blood, transports oxygen from the lungs to the rest of the body. With each oxygen mo...

Hunter on July 28 at 12:27AM

Explanation please... C over E

I picked answer E instead of C when I was in a class and never got an understanding of how I would know in the future that C is the correct answer. I didn't pick C because from the premise, I only got that the hemoglobin would be more effective than itself after picking up additional molecules, but I couldn't say for certain that it would be more effective than a different hemoglobin, even if it had already picked up three molecules. I see that E was using very strong S&N language, so I guess I can see why it was wrong. Still, even though this is a MBT, neither answer seems necessarily true.

2 Replies

Christopher on July 28 at 01:19AM

@Hunter, in a question like this you're looking for an answer that you can 100% conclude from the information above. Part of the reason why (E) is wrong is that it adds information about picking up oxygen "in or near the lungs," which doesn't have evidence within the question. The original information simply talks about hemoglobin transporting oxygen from the lungs to the rest of the body.

I can see what you're getting at with your objection to (C), but you're reading more than what is on the page. There's nothing in the question that suggests that hemoglobin molecules differ significantly from each other, so it's safe to assume that a hemoglobin molecule with 3 attached oxygen molecules would be more effective at picking up another oxygen molecule than a hemoglobin molecule with only 1 oxygen.

Does that help?

Hunter on July 29 at 06:49PM

It does help! Thank you, Christopher!