Final answer:
In a sealed chamber, the fluid levels in a manometer would typically remain unchanged during physical activity due to equal pressure distribution and assuming the chamber is airtight and the gas is not significantly compressed.
Step-by-step explanation:
When considering a manometer in a sealed chamber, the fluid levels would typically remain unchanged during physical activity. In a closed system where the manometer is designed to measure pressure changes within the chamber rather than atmospheric pressure, any increase in air pressure due to respiration would be distributed equally, thus leaving the manometer fluid levels unchanged.
This assumes the chamber is airtight and the increase in pressure due to physical activity is not enough to compress the gas significantly. The equal distribution of pressure is due to the principle stating that the pressure exerted by a fluid at a given level is the same throughout its horizontal plane. In an open-ended manometer, which measures the difference between atmospheric pressure and the pressure in the chamber, the fluid levels on either side would reach equal heights when both sides are open to the atmosphere, regardless of tube diameters.