Final answer:
Moose overcome the challenges of winter mobility with their long legs and special leg rotation at the shoulder, aiding in their movement through snow.
Step-by-step explanation:
Moose solve the winter mobility problem primarily by having really long legs, which are approximately 2 meters tall at the shoulder, and a special leg rotation at the shoulder, giving them a high vantage point to see predators and move through deep snow. They do not solve this problem through huge hollow hooves, walking in single file, or migrating to areas with no snow. Therefore, the correct answer to the question, “Moose solve the winter mobility problem by,” is option b: having really long legs, 2 meters tall at the shoulder, and a special leg rotation at the shoulder.