How many contractions per minute were required for the paramecium to maintain a relatively stable internal solute concentration and stay the same size?

Paramecia typically contract their contractile vacuoles at a rate of about one to three times per minute to maintain a stable internal solute concentration and prevent excessive swelling due to osmosis. This rate helps regulate the expulsion of excess water, allowing the organism to maintain its size and overall osmotic balance in freshwater environments. Adjustments in contraction frequency may occur in response to changes in environmental osmotic pressure.