Answer:si
Explanation:hope I helped
A. endoskeleton
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.
Fatty acids only
Acetyl coenzyme A is a biological molecule that is used in biochemical reactions. These biochemical reactions include the breakdown or hydrolysis of protein, carbohydrates and lipid molecules. The hydrolysis of these molecules in the presence of acetyl CoA produces energy and its primary function is fatty acid metabolism.