Fact: cold environments are usually white in color from being covered in snow
Question: Environments which are covered in snow are often white as a result of said snow and what other factor?

What's the answer? Choose from:
1). conditions which allow little if any heat to be produced or stored;
2). temperatures that are colder than a tropical environment;
3). cool air that flows in a circular pattern;
4). wind chill that meets warm fronts on occasion;
1).