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27 Jan 2021, 14:04
Kudos
Bookmarks
C
Be sure to select an answer first to save it in the Error Log before revealing the correct answer (OA)!
Difficulty:
15%
(low)
Question Stats:
77% (01:19) correct
23%
(01:31)
wrong
based on 286
sessions
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Not Attempted Yet
Scientists removed all viruses from a seawater sample and then measured the growth rate of the plankton population in the water. They expected the rate to increase dramatically, but the population actually got smaller.
Which one of the following, if true, most helps to explain the unexpected result described above?
(A) Viruses in seawater help to keep the plankton population below the maximum level that the resources in the water will support.
(B) Plankton and viruses in seawater compete for some of the same nutrients.
(C) Plankton utilize the nutrients released by the death of organisms killed by viruses.
(D) The absence of viruses can facilitate the flourishing of bacteria that sometimes damage other organisms.
(E) At any given time, a considerable portion of the plankton in seawater are already infected by viruses.
Which one of the following, if true, most helps to explain the unexpected result described above?
(A) Viruses in seawater help to keep the plankton population below the maximum level that the resources in the water will support.
(B) Plankton and viruses in seawater compete for some of the same nutrients.
(C) Plankton utilize the nutrients released by the death of organisms killed by viruses.
(D) The absence of viruses can facilitate the flourishing of bacteria that sometimes damage other organisms.
(E) At any given time, a considerable portion of the plankton in seawater are already infected by viruses.
28 Jan 2021, 05:22
Kudos
Bookmarks
Pre-thinking:
The two elements of the paradox are:
i) Remove all viruses (which are pathogens, expected to harm other organisms) from a seawater sample.
ii) The population of plankton got smaller.
Clearly, if there is a causal relationship, we are looking for an answer option that shows some way in which the viruses benefit the plankton. Let us examine the answer option.
(A) Viruses in seawater help to keep the plankton population below the maximum level that the resources in the water will support. This is an interesting option. While the option states that viruses play a role in eliminating some plankton, this would benefit the surviving plankton. However, this does not explain how the plankton population reduced, since, without the virus, the plankton population should still reach the level that the resources in the water support, and we do not know what that level is relative to the levels observed in the experiment. Eliminate.
(B) Plankton and viruses in seawater compete for some of the same nutrients. This shows a way in which viruses are detrimental to plankton. Eliminate.
(C) Plankton utilize the nutrients released by the death of organisms killed by viruses. Correct answer. This shows how viruses benefit plankton. If viruses are removed, they no longer kill the organisms and the nutrients are no longer released for usage by the plankton.
(D) The absence of viruses can facilitate the flourishing of bacteria that sometimes damage other organisms. If this were true, the population of other organisms is either unaffected, or expected to reduce. However, given that we do not know if plankton are among the organisms that are damaged by these bacteria, and the presence of a much cleaner option (C), we should eliminate this option.
(E) At any given time, a considerable portion of the plankton in seawater are already infected by viruses. This does not explain how viruses benefit plankton. Eliminate.
Hope this helps.
The two elements of the paradox are:
i) Remove all viruses (which are pathogens, expected to harm other organisms) from a seawater sample.
ii) The population of plankton got smaller.
Clearly, if there is a causal relationship, we are looking for an answer option that shows some way in which the viruses benefit the plankton. Let us examine the answer option.
(A) Viruses in seawater help to keep the plankton population below the maximum level that the resources in the water will support. This is an interesting option. While the option states that viruses play a role in eliminating some plankton, this would benefit the surviving plankton. However, this does not explain how the plankton population reduced, since, without the virus, the plankton population should still reach the level that the resources in the water support, and we do not know what that level is relative to the levels observed in the experiment. Eliminate.
(B) Plankton and viruses in seawater compete for some of the same nutrients. This shows a way in which viruses are detrimental to plankton. Eliminate.
(C) Plankton utilize the nutrients released by the death of organisms killed by viruses. Correct answer. This shows how viruses benefit plankton. If viruses are removed, they no longer kill the organisms and the nutrients are no longer released for usage by the plankton.
(D) The absence of viruses can facilitate the flourishing of bacteria that sometimes damage other organisms. If this were true, the population of other organisms is either unaffected, or expected to reduce. However, given that we do not know if plankton are among the organisms that are damaged by these bacteria, and the presence of a much cleaner option (C), we should eliminate this option.
(E) At any given time, a considerable portion of the plankton in seawater are already infected by viruses. This does not explain how viruses benefit plankton. Eliminate.
Hope this helps.
10 Feb 2021, 04:35
Kudos
Bookmarks
svasan05
Other side of A:
No virus - > plankton population surpass min level that the resources in the water will support
Then the paucity of resources -> Low population, is it make sense?
