# M01-L03 exercise — Sources, tools, and uncertainty

**Start:** M01-L02 and its saved context comparison.

Annotate the three claims in the original sample answer in this lesson. Then add a fourth claim: “The board's sensor cable is disconnected.” Explain whether a synthetic invalid tuple can establish it.

Create a revised answer of no more than 150 words and a source/check table. Each row must identify a source location, an actual executed result, or an explicit unknown. If you consult a live reference, record title, revision when shown, access date, and the relevant section. Do not reproduce a full third-party manual in your worksheet.