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.
Extinction refers to the eradication of an entire Species. Hope this helped!
Amino acids for health and proteion
The advantageous proteins that build larger molecules help prolong life life. If there is better survival and reproduction, it is more likely to pass onto the next generation. If it continues to be advantageous, the sequence of them change to support the life of the current species.
