Identify central idea of the text

The central idea of a text is its overall main point, the idea that ties every sentence together.
To find it, ask what single statement the whole passage is working to convey, not just what one line mentions.

Here is a complete example. Consider this passage: "By noon the market square had turned to chaos. Vendors shouted over one another, an overturned cart had spilled apples across the cobblestones, and children chased a runaway goat between the stalls."
Which choice best states the central idea?
(A) The market square had descended into complete disorder.
(B) A cart had overturned in the square.

Choice (A) covers the whole passage — the shouting, the spilled apples, and the runaway goat are all instances of the square's disorder.
Choice (B) is true but names just one detail, so it is too narrow to be the central idea.
A detail can be accurate and still fail, because it does not account for the rest of the passage.

The other trap is a choice that overstates the passage.
A choice claiming the market was permanently ruined would go beyond what the text actually shows.
So pick the statement broad enough to include every detail, yet careful not to say more than the passage supports.

Passage: "The morning the news broke, nothing in the Harlow house ran as it should. The cook forgot the bread in the oven, the children were sent to school in mismatched clothes, and no one remembered to feed the dog. Even the grandfather clock, always wound on Sundays, had stopped."
Which choice best states the central idea?
(A) A single piece of news has thrown the entire Harlow household into disorder.
(B) The Harlow family owns a grandfather clock that is wound on Sundays.
Choice (A) captures the whole passage — every detail shows the household in disarray — while (B) is just one small detail, so (A) is correct.

Passage: "The reef had changed in a single season. Fish that once crowded the shallows were gone, the coral had faded from bright orange to bone white, and the divers who came each year now surfaced in silence."
Which choice best states the central idea?
(A) A once-vibrant reef has suffered a dramatic decline.
(B) Divers visit the reef every year.
Choice (A) covers the whole passage, which is about the reef's overall collapse, while (B) reports only one detail, so (A) is correct.

Passage: "Mara had never spoken in front of a crowd, yet she steadied her hands, met the audience's eyes, and delivered every line. When she finished, the applause told her she had done more than survive — she had won them over."
Which choice best states the central idea?
(A) Mara overcame her fear and succeeded at public speaking.
(B) Mara will never feel nervous before a speech again.
Choice (A) matches what the passage shows, while (B) overstates it, claiming something the text never says, so (A) is correct.