Which statement identifies a characteristic of a scientific theory?
a. it’s a subjective
b. it’s a proven fact
c. it’s based on a opinion
d. it may change over time

The correct answer is B it"s a proven fact.

Explanation:

Any scientific theory is based upon many experiments ans observations.The experiment and observations are repeated many times to provide a scientific logic about that theory.

   A scientific theory is accepted only when that theory is logically proved by various experiment ,observations,statistical analysis etc.

answer: the rate of diffusion increases with increase in temperature.

increase in temperature, increases the molecular/particles speed (kinetic energy. diffusion means movement of particles through the material.

generally, the heavier the particle the more it interacts with the environment and more the temperature matters. so higher temperature results in higher diffusion.