1. Jonathan is training for a marathon in the city of Vancouver, which is at sea level. He is seeking advice on different training methods that will maximize his performance. What advice would you give him with respect to the following: 1) training at a higher elevation vs. training at sea level and 2) training in the cold winter vs. training in the hot summer. Discuss the pros and cons of each of the situations. Also mention safety issues that he may want to consider in each situation.