Pineapple contains a protein-digesting enzyme called bromelain. When added to gelatin, it results in the enzyme eating the proteins in the gelatin and prevents it from firming.

Based on this information, what does the pineapple contain that made it gelatin become watery?

Is it seeds; an enzyme called bromelain; sugars known as fructose

The pineapple contains an enzyme called bromelain that made the gelatin become watery.