Final answer:
The relative humidity decreases when temperature increases if the water vapor density remains constant. This is due to the increased capacity of warmer air to hold more water vapor. The ideal humidity in prep and packaging areas is 30-50% to balance comfort and product preservation.
Step-by-step explanation:
The ideal humidity level in the prep and packaging area is b) 30-50%. This range manages both comfort and prevents various forms of degradation or spoiling of packaging materials and products. Now, regarding the change in relative humidity with temperature, it's important to recall that as temperature increases, the air's capacity to hold water vapor also increases. If the water vapor density remains constant and the temperature rises, the relative humidity will decrease.
For example, if the relative humidity is 90.0% on a summer morning at 20.0°C, and later the temperature rises to 30.0°C with no change in water vapor density, the relative humidity will decrease because the warmer air could hold more water vapor at that temperature. Conversely, if the temperature drops and the water vapor content doesn't change, the relative humidity goes up, potentially reaching saturation point and leading to condensation (as dew or fog).