Final answer:
The suffix that means 'decrease' or 'deficiency' is '-penia', used in medical terminology to indicate the lack of substances such as cells or nutrients.
Step-by-step explanation:
This suffix is commonly used in medical terminology to indicate a lack of cells, nutrients, or essential substances in the body. For example, osteopenia refers to a decrease in bone density that is not as severe as osteoporosis. Similarly, leukopenia refers to a deficiency in white blood cells within the bloodstream. Another example is "leukopenia," where "leuko-" pertains to white blood cells, and the suffix signifies a shortage. This condition involves a lower-than-normal count of white blood cells in the bloodstream. The use of "-penia" aids in precise communication within the medical field, allowing professionals to describe conditions involving insufficiencies in cells, nutrients, or essential substances. Understanding these terms is crucial for accurate diagnosis and effective communication among healthcare providers.