Question 37·Easy·Words in Context
According to recent research, an exoplanet orbiting the red dwarf star TRAPPIST-1 may have an atmosphere rich in hydrogen. Because hydrogen is an efficient greenhouse gas, the atmosphere ______ heat that would otherwise escape into space, potentially making the surface warmer than expected.
Which choice completes the text with the most logical and precise word or phrase?
For vocabulary-in-context questions, first ignore the answer choices and paraphrase what the missing word must mean using nearby clues—especially cause-and-effect phrases like “because,” “therefore,” or contrasts like “however.” Here, “heat that would otherwise escape into space” tells you the atmosphere does the opposite of letting heat escape, so you think of a simple phrase like “keeps the heat in.” Then, compare that paraphrase to each option’s dictionary meaning and eliminate any that don’t fit the literal meaning or the scientific tone. This “paraphrase first, match second” method helps you avoid being distracted by hard or fancy-sounding words that don’t actually fit the sentence.
Hints
Look at the cause-and-effect relationship
The word “Because” at the start of the second sentence shows a cause-and-effect relationship. Think about what the atmosphere does as a result of hydrogen being an efficient greenhouse gas.
Focus on the phrase after the blank
Read carefully: “heat that would otherwise escape into space.” Ask yourself: without this atmosphere, what would the heat do, and with the atmosphere, what changes?
Check each choice in the sentence
Mentally plug each option into the sentence and ask: Does this describe a realistic physical effect an atmosphere could have on heat in a scientific context?
Step-by-step Explanation
Understand the scientific context
The sentence talks about an exoplanet with an atmosphere rich in hydrogen. It then says hydrogen is an efficient greenhouse gas. Greenhouse gases are known for affecting how heat moves between a planet and space.
Use the key clue: heat that would otherwise escape
Focus on the phrase “heat that would otherwise escape into space.” This tells you what would happen without the greenhouse gas: the heat would leave. Because it is a greenhouse gas, the atmosphere instead does the opposite: it keeps the heat from escaping and makes the surface warmer.
Match the meaning to the answer choices
We need a verb that means “keeps/holds onto heat instead of letting it escape.”
- compiles means gathers or collects information, usually data or documents.
- abolishes means ends or gets rid of something completely.
- retains means keeps or continues to hold something.
- advertises means promotes or publicly announces something. Only “retains” correctly describes an atmosphere that keeps heat that would otherwise escape into space.