In physical science, what does mya mean when referring to age?

What word is used to describe differences of individual organisms

When the cell concentrates potassium within, against the natural tendency of matter, it is performing a. passive diffusion b. facilitated diffusion c. active transport d. pinocytosis

The “ecological footprint” left by a citizen of a developed nation is about four times larger than that left by a citizen of a developing nation. why is this the case?