Maybe immune system and respiratory system
Viruses can multiply very quickly, and so they can go through natural selection at a much quicker rate, allowing certain vaccine resistant mutations to take over a population.
For a pre-event meal, rich sources of carbohydrates, such as bagels, muffins, and bread, should be eaten two to four hours before an endurance event. Eating a calorie dense meal 2 to 4 hours before an endurance event or smaller meals between 2 to 5 hours before, is absolutely essential for topping of muscle glycogen levels as well as providing blood glucose for the intense activity ahead.
Amino acids that have the possibility of participating in hydrogen bonds with suitable partners are those that have hydrophilic polar side chains.
