The normal level of cholesterol in human blood is (c) 140-180 mg. This range represents the typical concentration of cholesterol circulating in the bloodstream. Cholesterol is a lipid molecule essential for various physiological functions, including cell membrane structure, hormone synthesis, and bile acid production. However, elevated cholesterol levels, particularly low-density lipoprotein (LDL) cholesterol, can increase the risk of developing cardiovascular diseases such as heart attacks and strokes. Conversely, higher levels of high-density lipoprotein (HDL) cholesterol, often referred to as “good” cholesterol, are associated with a reduced risk of cardiovascular events. Therefore, maintaining cholesterol levels within the normal range is crucial for cardiovascular health. Lifestyle modifications such as adopting a healthy diet, regular exercise, and avoiding tobacco use can help manage cholesterol levels and reduce the risk of cardiovascular disease. Regular monitoring of cholesterol levels through blood tests is recommended as part of preventive healthcare.