DNA carries all of the information for your physical characteristics, which are essentially determined by proteins. So, DNA contains the instructions for making a protein. In DNA, each protein is encoded by a gene (a specific sequence of DNA nucleotides that specify how a single protein is to be made).
If a person falls asleep while talking, riding a bike, standing or while doing physical activities, it should not be taken casually. It is a sign of a severe sleep disorder.
Narcolepsy is a neurological condition where the brain's ability to control the sleep-wake cycle is disrupted. In such case the patient can fall into Rem sleep after falling asleep for 90 minutes.
Nolan's behavior indicates that he is suffering from Narcolepsy and must consult a sleep clinic.
Answer:
It is important to have more than one piece of evidence to make sure that the evidence is actually evidence. Or in other words, that the evidence is proven true. With only one piece of evidence, you can't be fully sure if calculations were correct, if the source was trustworthy, etc.
Multiple evidence is kinda like double checking math problems. If you don't do it, you can't be 100% certain the answer is correct.