Passage Summary: People think you can tell how old a rattlesnake is by its tail sections, but that's currently wrong because the tail breaks easily. The author claims it would work if the tail stayed intact, since a new piece grows every time the snake sheds its skin.

Conclusion: If rattlesnakes' rattles were not so fragile, one could accurately determine a snake's age by counting its rattle sections.

Reasoning: A new section is added to the rattle every time a snake sheds its skin (molts).

Analysis: The author identifies a 'missing link' between the act of molting and the passage of time. Even if the rattle never broke, counting sections only tells you how many times the snake has molted, not necessarily how many years it has lived. For the conclusion to hold, the argument requires the assumption that molting occurs at a regular, predictable rate relative to the snake's age. If a snake molts three times one year and zero times the next, the count is useless for determining age. Look for an answer that establishes a consistent relationship between molting cycles and time.