A radiator warms a room. Diagrams X and Y illustrate two different patterns of hot-air movement that warm the room. Which diagram and which reason describe how the room is heated by convection?
- Adiagram X; air density decreases when air is heated
- Bdiagram X; air density increases when air is heated
- Cdiagram Y; air density decreases when air is heated
- Ddiagram Y; air density increases when air is heated