According to the passage, how much of the water a redwood forest receives in a year can come from fog drip?
Read an Informational Passage · ELPAC Grades 3–5 reading. The correct answer, and the reasoning behind it.
A longer factual text, with questions about the main idea, supporting details and vocabulary.
Read the passage. Then answer the questions.
Drinking the Fog
Coast redwoods are the tallest trees in the world. Some grow more than 300 feet high. A tree that tall has a problem. Water is heavy, and pulling it from the roots all the way to the top takes a great deal of work.
Along the northern California coast, thick fog rolls in from the ocean on summer mornings. The fog drifts through the redwood branches and collects on the needles. Drops form, join together, and fall to the forest floor like light rain. Scientists have measured this. In some forests, fog drip supplies as much as a third of the water the trees receive in a year.
The trees also drink from above. Redwood needles can take in water straight from the fog, so the top of the tree does not have to wait for water sent up from the roots.
The fog helps other living things too. Ferns, banana slugs and young redwood seedlings all depend on the damp ground the fog leaves behind. Drier summers mean less fog, and less fog means a thirstier forest.
The question
Choose the best answer.
According to the passage, how much of the water a redwood forest receives in a year can come from fog drip?
- None of it
- Half of it
- All of it
- About a third of itCorrect answer
Why “About a third of it” is correct
This is a supporting-detail question that requires scanning for a number rather than reasoning. The second paragraph states that fog drip supplies 'as much as a third of the water the trees receive in a year'. Show the child how to hunt for the number words in a passage instead of rereading the whole thing.
Why the other answers are wrong
- None of it — The passage says the opposite: fog supplies a large share of the forest's water.
- Half of it — Half is a bigger fraction than the passage gives, and is a common misremembering of 'a third'.
- All of it — The passage never claims fog is the trees' only water; it also describes water pulled up from the roots.
Practice more of this
More reading practice for Grades 3–5, or see the ELPAC practice test for grades 3–5. For other grades, see free ELPAC practice tests by grade.
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