Answer:
When he figures out how to create sparks, Brian gets very happy and excitedly continues on with his duties.
Step-by-step explanation:
Brian examines the wall where the hatchet hit and finds a harder, darker stone that caused the hatchet to spark. He quickly learns that he can make sparks by swinging the hatchet against the stone. Delighted, Brian believes that he will be able to make a fire.
The creation of the sparks is the most significant use of the hatchet so far, representing a new phase in Brian's independent identity. Taking on this exciting new task brings Brian joy and a sense of purpose.