Answer:
a. The beaker absorbed energy that was released by the chemical reaction.
Step-by-step explanation:
Gustaf was watching an exothermic reaction, so the beaker got hot.
Exothermic reaction is one in which there is release of energy. In this process, energy production persists only through continuous supply of energy.
Gustaf was watching an exothermic reaction between two substances in a glass beaker. This reaction occurs with the release of energy because it is an exothermic reaction. In this way, the glass absorbed energy that was released by the chemical reaction.