In this paragraph, it is specified that limitations pertain to the compensation of glycogen. (scroll further down for my question)
But in the question below, the answer choices state that a dangerously long recovery period is what is the limitation. But doesn’t the 7th line form the end say, “It might seem that this interminably long recovery time in a large vertebrate would prove a grave disadvantage”? So, in fact, it’s not, right? Why is the answer not C but B?
(B) necessitate a dangerously long recovery period in large animals
The passage supports this statement with evidence. It mentions that the glycogen reserves of any animal, including large ones, are good for only about two minutes of maximum effort during anaerobic glycolysis. After that, a recovery period is required, during which the lactic acid produced needs to be reconverted into glucose via oxidative metabolism. This process can take a long time in large animals, leaving them vulnerable to attack until the acid is reconverted. For example, while a tiny shrew can replace its glycogen reserves in minutes, a gigantic dinosaur would have required more than three weeks to do so. So, option (B) is correct.
(C) produce energy more slowly than it can be used by large animals
On the other hand, option C is not supported by the passage. In fact, it suggests the opposite by stating that very large animals with low metabolic rates can survive well on sporadic food supply(Para 1), implying that the energy produced through anaerobic glycolysis is sufficient for their needs. So, option C is incorrect.
@HoldMyBeer Thanks for your input but I’m still in doubt. The reason I marked C was because of this line: “Whereas a tiny shrew can replace in minutes the glycogen used for maximum effort, for example, the gigantic dinosaur would have required more than 3 weeks.”, ie it is slower in big animals right?
But isn’t the context of option B, an assumption that the author says that a reader may have? Because it says, “It might seem that this interminably long time…would prove a disadvantage. Fortunately (contradicting the previous statement)------” Isn’t the word, “Fortunately” contradicting the previous idea? So this isn’t really a limitation right? This was my thought process. Let me know what you think
You’re correct in stating that the glycogen replacement is slower in large animals like dinosaurs, which takes up to three weeks compared to minutes for a small shrew. However, that fact pertains more closely to the recovery period after maximum exertion and the repayment of the “energy debt,” not the speed at which anaerobic glycolysis itself produces energy. The text doesn’t suggest that the process of energy production via anaerobic glycolysis is slower in larger animals, which would be necessary to support answer C. So, this interpretation is incorrect.
In regards to answer B, the use of the term “Fortunately” does not contradict the previous statement. The author initially acknowledges that the long recovery time “might seem” like a disadvantage, which sets up a potential argument. But then the author explains that because muscle glycogen is only used when necessary, large animals wouldn’t typically use up their entire reserves except in cases of panic or mortal combat. So, while the long recovery period might not always pose a significant problem, it still exists as a limitation of anaerobic glycolysis, making answer B the correct one.
The “Fortunately” clause is there to moderate the perceived disadvantage, not to erase it completely. This moderation does not negate the reality that if a large animal were to use up its entire glycogen reserves, the recovery period would be dangerously long, thereby making it vulnerable for a considerable amount of time. This idea is congruent with the scenario laid out in answer choice B.
So, in summary, while your doubts have some ground in terms of logic, it is crucial to understand the context and the specific point being discussed. Answer choice B more accurately reflects the limitations of anaerobic glycolysis as presented by the author.
