The curve is asymmetrical and resembles a skewed bell shape.

When temperature increases:

When comparing different gases at the same temperature, mass becomes the deciding factor in speed. Pogil Chemistry - sciphilconf.berkeley.edu

The curve becomes taller and narrower, shifting to the left . Most particles are "clumped" together at lower speeds. Effect of Molar Mass (Different Gases, Same Temp)

Students are presented with the premise that gas particles are not static; they are in constant, random motion. A critical realization students must make is that , even if the gas is at a uniform temperature.