What trade-off explains why arthropods dominate small sizes while vertebrates dominate large sizes?

Answer

The chitinous armor provides excellent lightweight support, but passive gas exchange limits size.

The exoskeleton offers superior strength relative to its weight and immediate defense, but the physics of passive gas exchange via tracheae severely limits how large an insect can grow, whereas internal skeletons allow for greater mass.

What trade-off explains why arthropods dominate small sizes while vertebrates dominate large sizes?
insectstructureanatomyBoneinvertebrate