General admission tickets for the Houston Museum of Natural Science get you access to all the permanent exhibits.
This includes the Cabinet of Curiosities, the Hall of Paleontology, the Hall of African Wildlife, the Hall of Gems and Minerals, the Hall of Ancient Egypt, the Hall of The Americas, the Welch Hall of Chemistry, the Energy Hall, and more.
Also on-site are the Cockrell Butterfly Center and the Burke Baker Planetarium. If you've got a full day, these are wonderful additions to your museum trip, and tickets for these attractions can be purchased in addition to your basic entry ticket (online or in-person).