Compressed air in scuba tanks cools off as a diver swims at deeper levels. The pressure in the tanks will __________.

The pressure in the tanks will **decrease**.

As the diver goes deeper, the external pressure increases due to the weight of the water above. However, the pressure inside the scuba tank is based on the gas stored inside, which may cool down as the gas expands during use. This cooling effect can lead to a decrease in internal pressure. Therefore, the pressure in the tanks will decrease as the diver swims deeper and uses the air in the tanks.