It has been observed that there is a strong need to promote health and independence…

It has been observed that there is a strong need to promote health and independence through dietary approaches in an individual’s life. With an aging population, people are less worried about their health and lifestyle which should not be the case. Of all the macronutrients, it has been seen that protein is the most satiating. Proteins are straight chain amino acids that are important macronutrients ( along with carbohydrates and fats ) that helps in the development of muscles, boosts metabolism, increases fat burning, lowers blood pressure, etc. Protein sources include animal meat, eggs, milk, cheese, soybeans, etc. However, excess consumption of animal meat protein is an environmental threat and hence, in recent years, alternate substitutes of protein like vegan protein are becoming a choice of individuals.
Which of the following is not an amino acid?