2. What must happen to this fuel—wood, coal, or gasoline—before it can make the engine do its work?
3. Did you ever wonder why it is that your body is always warm? It is very much like the engine.
4. What do you call this fuel that your body-engine uses? Just as the fuel for the steam engine must be burned if it is to make heat, even so must the food be burned in your body if it is to keep it warm and able to work. Of course the food in your body does not burn exactly as the wood and coal burn in the steam engine. It burns much more slowly—so slowly that you would not know that it burns at all if it were not that it always keeps your body warm.
Just as the steam engine needs the fuel if it is to do its work well, your body needs the best of food if it is to be healthy and do the best work. You have learned that all foods do not serve the same purpose equally well. For instance, some foods such as lean meat, eggs, and milk build up more muscle than other foods do; while others, such as fats, syrup, sugar and potatoes, give more heat than other foods.
5. What do all colored vegetables contain?
6. What kinds of foods do people living in the very cold climates need a great deal of?
7. What kinds of foods do people living in very warm climates need a great deal of?
TWO LITTLE PLANTS
Look at this lovely little plant with its pretty bright leaves and beautiful pink blossoms. Well may we ask what makes the little plant so healthy, strong, and pretty. It is a delight to the eye.