I need guideness on the physical and metabolic constraints limit cells size? And how an enormous cell encounter and adapations would help large cells survive?
One of the main reasons cells are small is due to the surface area/volume constraint.
Consider a ball. As it expands, its surface area expands at a slower rate than its volume. (You can check out the mathematics of that by looking at the volume of a sphere versus the surface area of a sphere.) In other words, as it expands its surface area/volume ratio gets smaller and smaller. Therefore, to have the largest surface area/volume ratio, the cells should be as small ...