In early 2014, the Centers for Disease Control and Prevention reported that Americans are living longer than ever, with life expectancies continuing to increase annually.

Height and puberty correspond to each other, but you've probably noticed that some teenagers get taller well after they've left puberty. Nutrition, gender and the body's own growth plates help determine the timing and velocity of that growth.

Puberty can be an awkward time of life. Hormone changes during puberty may cause your child to gain some weight.

When you turn 50 or 60, no one expects you to have the same energy levels you had in your teens and 20s. Slowing down as you age is normal, but experiencing chronic and extreme fatigue is not.

From infancy to late life, nutritional needs change. Children must grow and develop, while older adults must counter the effects of aging. The importance of age-appropriate nutrition during all stages of the life cycle cannot be overlooked.

Weight Watchers is a weight-loss program that has been around since the 1960s. The program offers tools, motivation and education to help participants in making the right decisions about food and exercise.

Nematodes are highly abundant, non-segmented worms that are present in a variety of habitats. Many are free-living (such as those that live in the soil), while others are parasitic and must attach themselves to a plant, insect, animal or human host to survive and reproduce.

The stages of life have been defined by cultures and religions in many ways. In ancient Greece, the human life cycle was mapped in seven-year periods. Today, most people recognize the human life cycle as having four or five distinct stages shared by all humans.

Throughout development from infancy to adulthood, normal vital signs change. Due to anatomical differences, what is normal for one age group could be abnormal for another. Normal pulse rate changes substantially from infancy to middle childhood. By age 12, the normal pulse rate approximates that of an adult.

Vitamin B-12, or cobalamin, is an important component for several metabolic reactions in the body. Although Vitamin B-12 deficiency is rare, it can result in anemia and serious cases of neuropathy and dementia. Daily recommendations for adults are 2.4 micrograms a day. B-12 is typically found in animal sources.