Why does methyl cellulose slow movements in euglena?

Methyl cellulose is a viscous substance that increases the viscosity of the surrounding medium. When euglena, a unicellular organism known for its motility, is placed in a solution of methyl cellulose, the increased viscosity creates resistance against its flagellar movements. This resistance hinders the euglena's ability to propel itself efficiently through the medium, resulting in slower movement.