To ensure proper protection for food during storage the bottom shelf should be at least 3 inches - 3 feet above the ground. This is to protect the food from pests and other organisms that may cause disease and health-problems to people who are going to consume such produce. It is a common practice done in the past and have evolved in the process of manufacturing these days.
The answer is c .. (that the bottom)
Real-world efficiencies are generally very high, in the 90 percent range. FALSE.
