Final answer:
To determine the meaning of 'apprehensive', an inference context clue is used based on the phrase 'his stomach was in knots', implying anxiety or nervousness about an upcoming event.
Step-by-step explanation:
You would use inference to determine the meaning of the word 'apprehensive' in the sentence given. The context clue provided by the sentence is the phrase "his stomach was in knots for days before he left", which suggests that Jamal is experiencing anxiety or nervousness about his upcoming first plane flight. Therefore, it can be inferred that 'apprehensive' means feeling anxious or fearful about a future event.