The passage indicates that research

Question

Option 1: has only been conducted using specific plants.

Option 2: has only been conducted by NASA.

Option 3: has not identified the sources of these chemical impurities.

Option 4: has only benefited long-term space exploration.

AfterBoards · Accepted Answer

**Option 1: has only been conducted using specific plants.** The passage tells us that the research was carried out using certain selected plants — scientists picked particular types of plants to experiment with rather than testing every plant in the world. **Why the other options are wrong:** - **Option 2** → The passage does not limit the research to just NASA; other scientists may have also been involved. - **Option 3** → The passage does not say that researchers failed to identify where the chemical impurities come from. - **Option 4** → The research has benefits beyond just long-term space exploration — it can also help people on Earth, such as by improving indoor air quality.

The passage indicates that research

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