Answer
the first one (im pretty sure)
Explanation:
Each enzyme's active site is suitable for one specific type of substrate – just like a lock that has the right shape for only one specific key. Changing the shape of the active site of an enzyme will cause its reaction to slow down until the shape has changed so much that the substrate no longer fits.
hot air rises up in the balloon and lifts the balloon up
The pressure will continue to build up eventually causing a release of pressure or an explosion.