Context: Vitamins and minerals are also nutrients. They do not provide energy, but they are needed for good health. Vitamins are organic compounds that the body needs in small amounts to function properly. Humans need 13 different vitamins. Some of them are listed below ( Table 1.1). The table also shows how much of each vitamin you need every day. Vitamins have many roles in the body. For example, Vitamin A helps maintain good vision. Vitamin B9 helps form red blood cells. Vitamin K is needed for blood to clot when you have a cut or other wound. Vitamin Necessary for Available from Daily Amount Required (at ages 913 years) Vitamin Necessary for Available from A Good vision B1 Healthy nerves B3 Healthy skin and nerves B9 Red blood cells B12 Healthy nerves C Growth and repair of tis- sues Healthy bones and teeth Blood to clot Carrots, spinach, milk, eggs Whole wheat, peas, meat, beans, fish, peanuts Beets, liver, pork, turkey, fish, peanuts Liver, peas, dried beans, leafy green vegetables Meat, liver, milk, shell- fish, eggs Oranges, grapefruits, red peppers, broccoli Milk, salmon, tuna, eggs Spinach, brussels sprouts, milk, eggs D K Daily Amount Required (at ages 913 years) 600 g (1 g = 1 106 g) 0.9 mg (1 mg = 1 103 g) 12 mg 300 g 1.8 g 45 mg 5 g 60 g Some vitamins are produced in the body. For example, vitamin D is made in the skin when it is exposed to sunlight. Vitamins B12 and K are produced by bacteria that normally live inside the body. Most other vitamins must come from foods. Foods that are good sources of vitamins include whole grains, vegetables, fruits, and milk ( Table 1.1). Not getting enough vitamins can cause health problems. For example, too little vitamin C causes a disease called scurvy. People with scurvy have bleeding gums, nosebleeds, and other symptoms. Minerals are chemical elements that are needed for body processes. Minerals that you need in relatively large amounts are listed below ( Table 1.2). Minerals that you need in smaller amounts include iodine, iron, and zinc. Minerals have many important roles in the body. For example, calcium and phosphorus are needed for strong bones and teeth. Potassium and sodium are needed for muscles and nerves to work normally. Mineral Necessary for Available from Calcium Strong bones and teeth Chloride Magnesium Proper balance of water and salts in body Strong bones Phosphorus Strong bones and teeth Potassium Muscles and nerves to work normally Muscles and nerves to work normally Milk, soy milk, leafy green vegetables Table salt, most packaged foods Whole grains, leafy green vegetables, nuts Meat, poultry, whole grains Meats, grains, bananas, orange juice Table salt, most packaged foods Sodium Daily Amount Required (at ages 913 years) 1,300 mg 2.3 g 240 mg 1,250 mg 4.5 g 1.5 g Your body cannot produce any of the minerals that it needs. Instead, you must get minerals from the foods you eat. Good sources of minerals include milk, leafy green vegetables, and whole grains ( Table 1.2). Not getting enough minerals can cause health problems. For example, too little calcium may cause osteoporosis. This is a disease in which bones become soft and break easily. Getting too much of some minerals can also cause health problems. Many people get too much sodium. Sodium is added to most packaged foods. People often add more sodium to their food by using table salt. Too much sodium causes high blood pressure in some people. 
 Question: what vitamin is important in blood clotting?
Output: vitamin k