CDMA (Code Division Multiple Access) and GSM (Global System for Mobiles) are shorthand for the two major radio systems used in cell phones. Both acronyms tend to group together a bunch of technologies run by the same entities. In this story, I'll try to explain who uses which technology and what the real differences are.
Dairy. Dairy products provide nutrients that are critical for bone health, including calcium, potassium and vitamin D. Dairy is also a source of protein. The benefit dairy provides for bones makes consumption especially critical for growing children, whose bone mass is developing.
Calcium is essential for strong bones and teeth, and it's also necessary for your nerves to function and your muscles to contract and relax properly. You get that calcium from the foods you eat. While there are many non-dairy foods that are rich in calcium, dairy is such an excellent source of calcium that it qualifies as a food group. According to the United States Department of Agriculture, you need about three servings of dairy every day. The downside of dairy is that it can be high in saturated fat.