Final answer:
Rickets is a deficiency disease caused by a lack of vitamin D, leading to improper bone development and deformities like bowed legs in children. It results from the body's inability to properly absorb calcium and phosphate, which are crucial for bone mineralization.
Step-by-step explanation:
One example of a deficiency disease caused by a long-term lack of vitamin D is rickets. Rickets results in improper bone development in children, primarily due to the malabsorption of calcium and a deficiency of vitamin D. This condition can lead to skeletal deformities, such as bowed legs, and is caused by an insufficient level of vitamin D which is necessary for the absorption of calcium and phosphate from the intestine.
Contrastingly, scurvy is associated with a vitamin C deficiency and is characterized by symptoms such as swelling, bleeding gums, and poor wound healing due to a lack of proper collagen formation. Other deficiency diseases include pellagra, caused by a deficiency in niacin, and anemia, which can result from various deficiencies including iron, vitamin B12, or folic acid. Deficiency diseases highlight the importance of a well-balanced diet rich in essential nutrients.