Question 22·Easy·Central Ideas and Details
Coral reefs thrive when tiny algae called zooxanthellae live inside coral tissue, providing the coral with much of its food through photosynthesis and giving reefs their bright colors. When ocean water becomes too warm for an extended period, corals become stressed and expel these algae. Without the algae, the coral turns white, a condition known as bleaching, and is more likely to die if stressful conditions persist.
According to the passage, what directly leads to coral bleaching?
For "According to the passage" detail questions, anchor yourself to key words in the question (here, "directly" and "bleaching"), then quickly locate those exact words or their definition in the text. Read one sentence before and after that spot to capture the full cause-and-effect relationship, turn it into your own simple summary (e.g., "X happens, then bleaching"), and finally eliminate any answer choices that introduce ideas the passage never mentions or that describe more general background causes rather than the specific, immediate one stated in the text.
Hints
Locate the key term in the passage
Scan the passage for the word "bleaching" and read the sentence it appears in, plus the sentence right before it.
Focus on cause and effect
When the passage defines bleaching, ask: What happens to the coral immediately before it "turns white"? That event is the direct cause you need.
Be careful about "directly"
Several problems can harm corals, but the question asks what directly leads to bleaching. Look for the last step just before bleaching happens, not an earlier or more general harmful condition.
Check each option against the text
For each answer choice, ask yourself: Does the passage actually say this leads to bleaching, or is it just something that sounds like it might be harmful? Eliminate any choice that is not clearly stated or implied in the bleaching description.
Step-by-step Explanation
Understand what the question is asking
The question asks: "According to the passage, what directly leads to coral bleaching?"
Focus on the words "directly leads" and "bleaching". You need the specific event the passage links immediately to bleaching, not just any general problem for corals.
Find where bleaching is described in the passage
Look back at the part of the passage that defines bleaching:
"Without the algae, the coral turns white, a condition known as bleaching, and is more likely to die if stressful conditions persist."
This sentence tells you what bleaching is (turning white) and what situation causes that to happen (being without the algae). Now check the sentence right before it to see what causes the coral to be without algae:
"When ocean water becomes too warm for an extended period, corals become stressed and expel these algae."
Put the two together in a cause-and-effect chain.
Identify the direct cause in the cause-and-effect chain
The passage gives a sequence:
- Warm water stresses the corals.
- Stressed corals expel the algae.
- Without the algae, the coral turns white (bleaching).
The direct cause of bleaching is the event that happens immediately before the coral turns white, not the earlier background cause (warm water). That event is the corals getting rid of the algae inside them.
Match the chain to the answer choices
Now compare each answer choice to the specific event that directly leads to bleaching in the passage. The only choice that matches the described direct cause—corals getting rid of the algae inside them—is:
D) Corals expel the algae that normally live within their tissues.