The answer is hard tissue.
Usually, hard tissue, such as bones and teeth or exoskeleton is much more preserved than soft tissue (organs, skin, etc.). Fossils become fossils by a process of mineralization. Hard tissues are more mineralized during life than organs. So it is no surprise that hard tissues take part in the process of mineralization and is preserved in fossils, unlike soft tissues.
"Survival of the fittest" is the one among the following choices given in the question which is an aspect of Darwin's theory that is shown as an example in this scenario. The correct option among all the options that are given in the question is the third option or option "c". I hope that this answer has helped you.
