C Fossils allow scientists to have an idea of the time scale that traits evolved.
Answer:
Natural selection. It is simply the process by which random variations that give an individual a favorable adaptation to its environment survive to be passed on to offspring.
In the question stated above, it is very likely that the patient is facing receptive or sensory issues. This is clear when he mistakes one stimulus for another. This might be because he sees one thing but can not distinguish it for another, or he's having problems differentiating one tactile stimulus for another. Either way, the system compromised is the patient's sensory system.