Which of the following situations demonstrate a direct energy transfer

Question

1. When the traffic signal turns red automobile, stop.
2. When water is boiled, steam is produced.
3. After a field plowed and fertilized corn is planted.
4. When the fire alarm rings, firetrucks rush off.
5: a letter has the correct postage, the carrier delivers it

Answer 1

2. When water is boiled, steam is produced.