What outdoor activity is Cassia excited to undertake based on stories about nature that her family has told her?

A few days after the showing, Cassia joins the class for hiking. It's the first time her generation has experienced this type of activity, and she is very excited about it. They start with the basics, climbing a small hill. This does not disappoint Cassia. Her family is familiar with nature, and they have told her about it. Her grandfather used to go hiking himself. Her mother works at the Arboretum and has told her about plants and trees. Cassia knows that even though the hill isn't very high, it will still be a challenge to climb because of the foliage. She is ready for the challenge.