Read the passage: 'The mantis shrimp has one of the most complex visual systems of any animal. While humans have three types of color receptors in their eyes, the mantis shrimp has sixteen. Despite this, research suggests the mantis shrimp may not actually perceive more colors than humans — instead, its visual system may process color in a fundamentally different way, optimized for rapid classification rather than nuanced discrimination.' What is the MAIN IDEA of this passage?

The MAIN IDEA is the central message or argument of a passage — the point the author most wants to convey. The passage introduces the mantis shrimp's remarkable visual complexity (16 vs. 3 color receptors) but then qualifies the natural assumption: rather than simply seeing more colors, the mantis shrimp may process color differently. The MAIN IDEA therefore captures BOTH parts of this: the extraordinary visual system AND the nuanced finding about how it may work differently, not just more. TECHNIQUE for finding main idea: (1) Read the entire passage first; (2) Ask: what is every sentence talking about? (mantis shrimp vision); (3) What does the author ultimately want you to understand? (that the visual complexity doesn't work the way you'd expect — it's qualitatively different, not just quantitatively more); (4) The main idea should be broader than any single detail but specific enough to differentiate from the other options. COMMON DISTRACTORS on ASVAB paragraph comprehension: (1) Too narrow — just one detail, not the whole point; (2) Too broad — the general topic without the specific point; (3) Opposite or contradictory; (4) Not mentioned at all. In this passage: Option A (most intelligent) — not mentioned; Option C (humans have better vision) — opposite of what's stated; Option D (identical systems) — opposite of what's stated. The ASVAB paragraph comprehension subtest has 11 questions in the paper-based version. Each question refers to a short passage (2-8 sentences). Always read the entire passage before answering, and refer back to the passage when answering.