<span>A. endoskeleton
</span>Endoskeleton is not a characteristic of Arthropods that has attributed to their diversity and success. Endoskeleton is defined as inner characteristics of the skeletal feature of an organisms such as bears, humans, fish and etc.
Exoskeleton on the other hand is the trait by which arthropods posses. It is skeletal feature that is described outside or is extrinsic, this is evident as crabs have their skeletons outside of their body.
The flow of energy starts in in you arms. You put your hands together, and use your arms to move your hands back and forth, this is kinetic energy. Your hands rubbing together causes the molecules to bump into each other, this is friction. As the molecules bump into each other they begin to move faster, and the fast movements of the molecules is what creates heat.
The mitochondria is the powerhouse of the cell because it produces ATP, which is energy.
