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ATB - Ability to Benefit Reading Comprehension Skills Questions and Answers

Read the following passage and answer the question: 'The Cambrian explosion, a period of rapid evolutionary change, saw the emergence of most major animal phyla.
However, the fossil record from this era is incomplete, leaving scientists to debate the exact timeline and causes.

Some theories point to environmental factors, such as an increase in oxygen, while others suggest genetic innovations were the primary driver.' Which of the following is the main idea of the passage?

Select your answer

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These practice questions were written with AI tools. They are not real exam questions. Exam facts are checked against the official sources listed below. Not reviewed by a subject-matter expert. Editorial policy

Sources & references

Exam facts on this page (fees, format, dates, passing scores) are checked against these official sources; the date is our last check. Editorial policy

  1. fsapartners.ed.gov — Eligibility, passing score · verified Oct 2026
  2. secure-media.collegeboard.org — Test delivery, retake policy · verified Nov 2026
  3. accuplacer.collegeboard.org — Time limit · verified Oct 2026