input question: Improve posture of kids.

output answer: Let them sit on exercise balls during homework.

input question: The best form of head for making watermelon

output answer: The microwave oven is the best for making them.

input question: What can I use in case of emergency if I don't have a candle?

output answer:
Use a crayon, light the end of a bit of the paper, it will burn for about 30 min, just set it on a large plate in case it falls over.