The passport card can be used at U.S. land and sea ports of entry when arriving from Canada, Mexico, the Caribbean and Bermuda. The card may not be used to travel by air.
A refrigerator maintains a temperature a few degrees above the freezing point of water. Optimum temperature range for perishable food storage is 3 to 5 Â°C (37 to 41 Â°F).emperature settings for refrigerator and freezer compartments are often given arbitrary numbers by manufacturers (for example, 1 through 9, warmest to coldest), but generally 3 to 5 Â°C (37 to 41 Â°F) is ideal for the refrigerator compartment and â18 Â°C (0 Â°F) for the freezer.
To keep food from spoiling, a refrigerator must maintain a temperature between 37 and 41 degrees Fahrenheit. Food is kept in an insulated space, and cooling is provided by a heat pump. Before the invention of the refrigerator in 1913, ice houses and ice boxes were used. They are still used in some areas of the world as of 2014.