<span>Personal protective equipment is only helpful if regulations for using it are followed carefully. If it is not worn and used properly, then it will not function properly and it might not provide the protection that is needed in the situation. For example, a helmet is only effective if it is fitted properly and snugly on the head. Otherwise it could fall off in an accident and be rendered useless.</span>
It shows the evolution of an being. "Fossil record, history of life as documented by fossils, the remains or imprints of the organisms from earlier geological periods preserved in sedimentary rock." from https://www.britannica.com/science/fossil-record
The continued presence of vestigial structures suggests that these structures do not have a great impact on fitness, like in the whale, because even with these structures, the whale has been able to survive and reproduce.