Question 145·Easy·Central Ideas and Details
Entomologists wanted to learn how path features influence ants’ foraging decisions. In an experiment, they set two identical dishes of food an equal distance from an ant colony. One path to a dish was lightly brushed with a sugar-water solution, while the other path was left untouched. Although the dishes contained the same type and amount of food, 80% of the ants followed the sugared path. The researchers suggest that the sugary scent acted as a cue, signaling to the ants that the marked route was more promising.
Which choice best states the main idea of the text?
For main idea questions, first quickly restate the passage in 1–2 simple sentences, focusing on what the experiment or paragraph is showing overall, not on small details. Then, eliminate any answer that conflicts with key facts (like controlled variables in an experiment) or that focuses on something the text only mentions in passing. The correct choice should match your brief summary and be supported by the entire passage, not just one phrase.
Hints
Focus on the experiment setup
Look at how the researchers designed the experiment: what did they keep the same between the two dishes, and what did they change?
Use the result and the researchers’ suggestion
Pay special attention to the sentence about 80% of the ants and the sentence starting with “The researchers suggest…”—what are the researchers saying explains the ants’ choice?
Eliminate choices that conflict with the details
Check each answer against the facts: the food type and amount were the same, and the distance was the same. Which choices disagree with those details or claim the opposite of what the ants did?
Step-by-step Explanation
Identify the task: main idea
The question asks for the main idea of the text. That means you need a choice that sums up the overall point of the experiment and the researchers’ conclusion, not just a detail.
Summarize the experiment in your own words
Restate the passage briefly:
- Two dishes of food were set the same distance from the ant colony.
- The dishes had the same type and amount of food.
- One path was brushed with sugar-water; the other path was not.
- About 80% of the ants chose the sugared path.
- Researchers think the sugary scent was a cue that made that route seem better.
This summary should guide you toward what the passage is mainly showing.
Extract the central point from the summary
Ask: What is the big takeaway from this experiment?
- The food itself was the same, so the difference is not the food’s sugar content.
- The distance was the same, so the difference is not distance.
- The main difference is the scented path versus the plain path, and most ants chose the scented route.
So the central idea is about how a marked (scented) path affects which identical food source ants go to.
Match your central idea to the answer choices
Now compare your central idea to the options:
- A talks about choosing food based only on sugar amount in the food, which the experiment rules out because both dishes had the same food.
- C says ants usually ignore scent cues, which is the opposite of what happened here (80% followed the scented path).
- D says distance is the main factor, but distance was controlled and equal.
- B says that marking a path with an attractive scent can strongly influence which food source ants select, which exactly matches what the experiment showed.
Therefore, the correct answer is: B) Marking a path with an attractive scent can strongly influence which food source ants select.