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In a paper published in Science Advances, an international team of researchers have examined traits of marine megafauna species to better understand the potential ecological consequences of their extinction under different future scenarios. 

Defined as the largest animals in the oceans, with a body mass that exceeds 45kg, examples include sharks, whales, seals and sea turtles. These species serve key roles in ecosystems, including the consumption of large amounts of biomass, transporting nutrients across habitats, connecting ocean ecosystems, and physically modifying habitats. Traits, such as how large they are, what they eat, and how far they move, determine species' ecological functions. As a result, measuring the diversity of traits allows scientists to quantify the contributions of marine megafauna to ecosystems and assess the potential consequences of their extinction.  

The team of researchers -- led by Swansea University's Dr Catalina Pimiento -- first compiled a species-level trait dataset for all known marine megafauna to understand the extent of ecological functions they perform in marine systems. Then, after simulating future extinction scenarios and quantifying the potential impact of species loss on functional diversity, they introduced a new index (FUSE) to inform conservation priorities.  

The results showed a diverse range of functional traits held by marine megafauna, as well as how the current extinction crisis might affect their functional diversity. If current trajectories are maintained, in the next 100 years we could lose, on average, 18% of marine megafauna species, which will translate in the loss of 11% of the extent of ecological functions. Nevertheless, if all currently threatened species were to go extinct, we could lose 40% of species and 48% of the extent of ecological functions. Sharks are predicted to be the most affected, with losses of functional richness far beyond those expected under random extinctions.  

(Adapted from https://www.sciencedaily.com/) 

Câu 44. Which of the following best serve as the title of the passage? 

A. How marine megafauna species’ extinction affects the ecology 

B. The consequences of trait examination of marine megafauna species 

C. What should be examined in the research in marine megafauna species? 

D. The causes of marine megafauna species’ extinction 

Câu 45. According to paragraph 2, the following are the main roles of the largest animals in the oceans, EXCEPT _______________. 

A. consuming large amounts of biomass B. transporting nutrients across habitats 

C. associating ocean ecosystems D. mentally modifying habitats 

Câu 46. The word “determine” in paragraph 2 is closest in meaning to ______________. 

A. affect B. establish C. describe D. cover 

Câu 47. The word “they” in paragraph 3 refers to _____________. 

A. researchers B. ecological functions C. marine systems D. future extinction scenarios 

Câu 48. According to paragraph 4, what proportion of ecological functions could we lose if all currently threatened species became extinct? 

A. nearly one fifth B. more than one tenth C. two fifths D. nearly a half 

Câu 49. The word “translate” in paragraph 4 most probably means ___________. 

A. interpret B. increase C. cause D. require 

Câu 50. As mentioned in the passage, which of the following is TRUE? 

A. The animals weighing about 45kg are classified as the largest ones in the ocean. 

B. Measuring the extinction of marine megafauna allows scientists to know the consequences to ecosystems. 

C. The species guessed to be the most affected by random extinction are sharks. 

D. The researchers now have known all the extent of ecological functions of marine megafauna.