Look at some up some videos about like eureka math or khan Academy
Based on this observation you would predict that the MISFOLDED BETA AMYLOID PROTEINS COULD NOT BE REFOLDED BY THE CHAPERONE PROTEINS.
Chaperon proteins are proteins which assist newly formed proteins to form correctly. A protein that is already mis-folded can not be refolded by the chaperone proteins.
The fossil record shows a sequence from simple bacteria to more complicated organisms through time, it is very reliable because it is physical evidence and by studying fossils, scientists can learn how much (or how little) organisms have changed as life developed on Earth.