Final answer:
Essential amino acids and essential fatty acids are nutrients that must be obtained from the diet. Omega-3 alpha-linolenic acid and omega-6 linoleic acid are essential fats, while Vitamins A and K are examples of essential, fat-soluble vitamins.
Step-by-step explanation:
The correct type of substance for each nutrient or vitamin is as follows: essential amino acids are those that the body cannot synthesize and must be obtained through the diet, while essential fatty acids are types of fats that are also not synthesized by the body and must be obtained from dietary sources. Two examples of essential fatty acids are omega-3 alpha-linolenic acid and omega-6 linoleic acid, both necessary for forming cell membrane phospholipids. Vitamins are essential organic molecules required in small quantities; for example, Vitamins A and K are essential and fat-soluble, with Vitamin A important for maintaining connective tissues and Vitamin K being crucial for blood clotting.