Do all species evolve at the same rate? explain.?

Nope. Species with a shorter generation time, and inhabiting a changing environment (implying changing selection pressures), tend to evolve faster.

No, species get lucky and have an adaptation/mutation that lets them survive better and/or reproduce more. These mutations are very rare and do not occur at regular intervals throughout all species. However, they do generally happen eventually to every species, or else the species dies out. Hope its not confusing.

There are a number of reasons in plants:

The origin of the plant - plants originally from sub-tropical or tropical areas will transpire at a higher rate than those originally from arid or semi-arid areas.

The size of the plant (larger leaf surface area = more transpiration).

The metabolic rate of the plant = plants with a higher metabolism have a higher transpiration rate.

The amount of water in the soil - plants that have access to more soil water will transpire at a higher rate than those which don't.

Availability of nutrients - plants which have adequate nutrient supplies have higher metabolic rates than those which don't....!!!!

NO.

The speed and tempo of evolution is different in different forms.

See sphenodon on the other hand where evolution has become stagnant.