The correct answer is B. Proteins.
Enzymes are proteins that catalyze, or speed up, chemical reactions. They are essential for life, as they are responsible for the many chemical reactions that take place in the body. Enzymes are found in all living things, from bacteria to plants to animals.
Alkaloids are a class of organic compounds that are found in plants. They are often bitter and have a variety of physiological effects, including some that are toxic. Carbohydrates are a class of organic compounds that are made up of carbon, hydrogen, and oxygen. They are the main source of energy for the body. Lipids are a class of organic compounds that are made up of carbon, hydrogen, and oxygen. They are important for the storage of energy and for the formation of cell membranes.
Here is a brief explanation of each option:
- Option A: Alkaloids are a class of organic compounds that are found in plants. They are often bitter and have a variety of physiological effects, including some that are toxic. Enzymes are not alkaloids.
- Option B: Proteins are large molecules that are made up of amino acids. They are essential for life, as they are responsible for the many chemical reactions that take place in the body. Enzymes are proteins.
- Option C: Carbohydrates are a class of organic compounds that are made up of carbon, hydrogen, and oxygen. They are the main source of energy for the body. Enzymes are not carbohydrates.
- Option D: Lipids are a class of organic compounds that are made up of carbon, hydrogen, and oxygen. They are important for the storage of energy and for the formation of cell membranes. Enzymes are not lipids.