@Eiman-Khan please make sure you are reading previous discussion threads before starting a new thread.
Your question here has already been asked and answered. Reposting @Naz's response here for your reference.
The conclusion of the argument is, "Seemingly inconsequential changes in sea temperature due to global warming eventually result in declines in fish and seabird populations." We are told that a rise of just two degrees prevents the vertical mixing of seawater. This, in turn, restricts the availability of upwelling nutrients to phytoplankton. And finally we are told that zooplankton, which feed the rest of the food chain, feed on the phytoplankton. So, the declines are inevitable because zooplankton will have a decline in their food source.
The statement that zooplankton feeds upon phytoplankton helps support the conclusion that declines in the fish and seabird population are inevitable because the phytoplankton will not have the nutrients they require, which will cause them to diminish, which in turn will cause the zoo plankton that feed on phytoplankton to diminish. This will result in the rest of the food chain diminishing accordingly. Thus, answer choice (C) "It helps show how global temperature changes affect larger sea animals indirectly," is correct.
The statement is not made in order to give an example of the ways in which vertical mixing of seawater affects feeding habits. It is a premise that is included to help support the conclusion. We are never told that vertical mixing of seawater affects feeding habits. We are merely told that the decline of the food chain is inevitable because zooplankton, which feed the rest of the food chain, will diminish due to the declining population of phytoplankton that will not have the nutrients they require. This does not pertain to feeding habits. More so it touches upon food sources diminishing as a whole. Thus, answer choice (B) is not correct.
Hope that was helpful! Please let us know if you have any other questions.
DChabSeptember 18, 2019
Hi Mehran,
I have seen the comment about reading through other messages before posting comments on several threads. However if the explanations were posted in the review section as expected you would not be consistently having this problem. To expect users to "sift" through multiple message threads per question is not a good use of study time.
