Which statement best reveals the central idea of the text?

The reader can infer that not seeing a reaction can be just as useful to an investigation as seeing one.

PART A: How does the arrival of the complaint about the foaming pond affect the investigation?

PART B: Which sentences from the passage best support your answer in part A?

Read the sentences.

Why did the author most likely choose to end the text with the investigator leaving the lab but receiving a new call about contamination?

What inference can be made about the problem based on the pattern the investigator discovered? Support your answer with evidence from the text.