TOEFL Reading Practice Test #12

Correct Answer: D) High temperatures.

Explanation: The passage outlines that sunlight, water, and carbon dioxide are essential for photosynthesis, but it does not mention high temperatures as a requirement. In fact, many photosynthetic organisms are found in cool or even cold environments, showing that high temperatures are not a necessity.

Correct Answer: C) To reduce water loss while performing photosynthesis.

Explanation: CAM photosynthesis allows desert plants to open their stomata at night instead of during the day. This adaptation reduces water loss in hot, dry conditions. The other options do not reflect the main advantage of CAM photosynthesis, which is focused on conserving water.

Correct Answer: A) The ability of photosynthetic organisms to survive in extreme environments.

Explanation: The phrase "remarkable adaptations" highlights the specialized strategies developed by photosynthetic organisms to thrive in extreme environments, such as deserts or polar regions. Other choices either misinterpret the context or do not reflect the main idea of the paragraph.

Correct Answer: A) Unique.

Explanation: "Specialized" refers to adaptations that are unique and specifically suited for certain functions. In this context, it describes the pigments adapted for capturing light under low-light conditions. "Complex" and "simple" do not fit the context, and "necessary" does not convey the idea of being specifically tailored.

Correct Answer: C) Polar organisms use specialized pigments to capture more light energy.

Explanation: The passage notes that algae and mosses in polar regions have evolved pigments that are better suited for capturing the limited light available. This adaptation allows them to photosynthesize even under the low-light conditions of polar environments. Other options misinterpret the timing or nature of photosynthesis in polar regions.

Correct Answer: B) Some desert plants have developed unique adaptations to conserve water and perform photosynthesis.

Explanation: Paragraph 2 discusses various strategies that desert plants use, such as CAM photosynthesis, to reduce water loss while still carrying out photosynthesis. The other options either generalize the strategies too much or provide incorrect information, such as the idea that all desert plants use CAM photosynthesis.

Correct Answer: C) From hydrogen sulfide.

Explanation: Chemosynthetic bacteria rely on hydrogen sulfide, which is emitted from hydrothermal vents, as their energy source. This process is distinct from photosynthesis, which uses sunlight. The other options incorrectly attribute energy sources that are not relevant for these bacteria.

Correct Answer: C) Passes through.

Explanation: In the context of the passage, "penetrates" refers to light passing through ice or snow to reach photosynthetic organisms below. This usage aligns most closely with "passes through." Other options, like "reflects" or "stops," do not fit the context of light reaching organisms beneath a surface.

The correct answer is D. The sentence fits best at point 4, immediately after the discussion of how these adaptations help organisms endure extreme environments. It adds a concluding statement that emphasizes the significance of these adaptations in allowing survival in inhospitable habitats. Placing it earlier would disrupt the explanation of the specific strategies and pigments used by these organisms.

Correct Answers: A, C, and D.

A) Some plants in deserts use specialized strategies to conserve water while photosynthesizing.
The passage discusses adaptations like CAM photosynthesis, highlighting strategies that desert plants use to conserve water.

C) Polar organisms use specialized pigments to capture light in low-light conditions.
The passage mentions how polar organisms have evolved pigments to capture light effectively, even in the dim conditions of polar environments.

D) Chemosynthetic bacteria rely on hydrogen sulfide as an energy source rather than sunlight.
This point captures the distinct process used by chemosynthetic bacteria, an important example of non-sunlight-dependent photosynthesis in extreme environments.

Incorrect Choices:

B) The ability to photosynthesize in extreme environments is rare and poorly understood.
The passage suggests that this ability is well-adapted and documented, not rare or poorly understood.

E) Photosynthesis can only occur in environments with abundant sunlight.
This contradicts the passage, which includes examples of photosynthesis in low-light and non-sunlight conditions.

F) Some photosynthetic organisms have evolved adaptations that allow them to survive in harsh environments.
While generally true, this choice is too vague compared to the more specific details given in A, C, and D.