Answer
A magnifying glass would magnify less when immersed in water.
Work Step by Step
Light refracts less when it travels between the water and the glass, and vice versa, compared to when the magnifying glass is in air.
This is because the speed of light doesn't change as much when light enters the glass from water compared to when it enters from air. The amount of refraction decreases, the light's path is changed by a smaller amount, and the magnification decreases to be closer to 1 (i.e., it magnifies less).