Passage Summary: Eating more produce in middle age helps prevent strokes later in life, likely because the folic acid in those foods prevents a certain amino acid from clogging up your arteries.

Reasoning: Fruit and vegetable consumption in middle age reduces stroke risk; these foods contain folic acid; low folic acid is linked to high homocysteine; high homocysteine contributes to blocked arteries.

Analysis: This is a 'Most Strongly Supported' question, so we need to find a statement that follows logically from the chain of facts provided. The stimulus links low folic acid to high homocysteine, and high homocysteine to blocked arteries, which are a primary cause of strokes. Therefore, it is highly probable that high levels of homocysteine are a significant factor in increasing one's risk of stroke. Look for an answer that synthesizes these biological links without making an overly broad or absolute claim.