Nhận biết (M1)

As complex lifecycle parasites, Anisakis sp. and Capillaria parophrysi require multiple host species throughout their development. Extrapolating from parasite counts on walleye pollock and seven other fish species collected from Puget Sound from 1880 to 2019, Chelsea Wood et al. found that the abundance of three-host parasites, such as Anisakis sp., negatively correlated with rising average annual sea temperatures; the abundance of two-host parasites, such as C. parophrysi, was largely stable. Noting that fish and other marine vertebrates are especially vulnerable to climate change, Wood et al. observed that all three-host parasites in the study depend on at least two vertebrate species, while all two-host parasites depend on only one, suggesting that _______

Which choice most logically completes the text?

• A.

  population size and density of the eight fish species examined in the study were likely largely unaffected by rising sea temperatures.

• B.

  although Anisakis sp. and C. parophrysi both require walleye pollock as a host, C. parophrysi was more adversely affected by warming-driven changes in the walleye pollock population than Anisakis sp. was.

• C.

  a parasite's sensitivity to warming temperatures is negatively correlated with the number of unique vertebrate species it depends on throughout its life cycle.

• D.

  warming-induced population changes among Puget Sound vertebrates may have suppressed some parasite populations, but there were no changes among the eight studied host species that affected two-host parasite abundance.