Answer:
Camps, friends, and across
Step-by-step explanation:
The camps, friends, and cross is not supposed to be there instead it is supposed to be "Gabriel once camped with his friends in his backyard. They stargazed and located planets and other constellations. Suddenly, they saw a shooting star across the sky, which thrilled the boys!" If it was put like that then it would make more sense.
Hope I helped you!