GRE Verbal Practice Test 19 (with Answers)

Text Completion

Questions 1–5.

1 The deep sea was long assumed to be almost , but expeditions have revealed thriving communities around hydrothermal vents.

2 Octopuses are masters of , able to change both the colour and the texture of their skin to blend into their surroundings.

3 Although overfishing (i) the cod population in the 1990s, the stock has shown signs of a (ii) recovery since fishing limits were imposed.

4 Whales were once hunted almost to extinction, but international protection has allowed several species to in number.

5 The plankton bloom was so that it could be seen from satellites as a swirl of green across hundreds of kilometres of ocean.

Sentence Equivalence

Questions 6–10. Select the TWO correct answer choices.

Reading Comprehension — Passage 1

Questions 11–15 are based on the passage below.

In 1977, scientists exploring the floor of the Pacific Ocean near the Galápagos Islands made a discovery that overturned basic assumptions about life. Around hydrothermal vents — cracks in the sea floor where volcanically heated water emerges — they found dense communities of giant tube worms, clams and crabs living in total darkness, more than two kilometres below the surface.

Until then, nearly all known ecosystems ultimately depended on sunlight captured by plants and algae through photosynthesis. The vent communities instead rely on chemosynthesis: bacteria that obtain energy from chemicals such as hydrogen sulphide in the vent water form the base of the food web. Some biologists have suggested that life on Earth may have originated in similar environments, and the discovery has encouraged astronomers to consider whether moons with hidden oceans, such as Jupiter's Europa, might also support life.

📚 Glossary · কঠিন শব্দের অর্থ

Word	বাংলা অর্থ	English meaning
hydrothermal	জলতাপীয়	relating to hot water heated within the Earth
chemosynthesis	রাসায়নিক সংশ্লেষণ	making food using energy from chemicals
originated	উৎপত্তি হয়েছে	began or came into existence

Reading Comprehension — Passage 2

Questions 16–20 are based on the passage below.

As the oceans absorb carbon dioxide from the atmosphere, they become more acidic, a process known as ocean acidification. Since the Industrial Revolution, the surface ocean has absorbed roughly a quarter of human carbon dioxide emissions, slowing the warming of the atmosphere but lowering the pH of seawater.

The consequences are most serious for organisms that build shells or skeletons from calcium carbonate, such as corals, oysters and some plankton, because acidic water makes these structures harder to form and easier to dissolve. Laboratory experiments show that some species can adapt, at least partly, while others suffer reduced growth. Because these organisms underpin many marine food webs and fisheries, scientists warn that acidification could have far-reaching effects even in regions where the water does not become noticeably warmer.

📚 Glossary · কঠিন শব্দের অর্থ

Word	বাংলা অর্থ	English meaning
acidification	অম্লীকরণ	becoming more acidic
calcium carbonate	ক্যালসিয়াম কার্বনেট	the mineral that forms shells and chalk
underpin	ভিত্তি হিসেবে কাজ করা	support from below