Passage Summary: Scientists believe a certain fat helps eyes develop because babies who don't get much of it see worse than those who do. They also noticed that premature babies have weaker vision.

Conclusion: A specific type of fat called P-fat is essential for the proper development of human eyesight.

Reasoning: Babies on low P-fat formulas have worse vision than breastfed babies, and babies born prematurely also tend to have poorer eyesight.

Analysis: The argument presents a correlation between P-fat intake and vision quality, but it leaves the mention of premature babies as an unexplained data point. To strengthen the hypothesis, we need to bridge the gap between prematurity and P-fat levels. If you find an answer choice suggesting that premature babies are naturally deficient in P-fat—perhaps because it is usually absorbed in the final weeks of pregnancy—the argument becomes much stronger. Look for information that turns the 'premature baby' fact into additional evidence for the P-fat theory.