The correct answer is A. Proteins.
Antibodies are proteins that are produced by the body’s immune system in response to an infection or other foreign substance. They bind to specific antigens, which are molecules that are found on the surface of bacteria, viruses, and other pathogens. This binding helps to neutralize the pathogen and prevent it from causing disease.
Lipids are a type of molecule that is made up of carbon, hydrogen, and oxygen atoms. They are found in the cell membrane, which is the outer layer of cells. Lipids are also found in fat, oil, and cholesterol.
Carbohydrates are a type of molecule that is made up of carbon, hydrogen, and oxygen atoms. They are the body’s main source of energy. Carbohydrates are found in foods such as bread, pasta, rice, and potatoes.
Nucleic acids are a type of molecule that is made up of carbon, hydrogen, oxygen, nitrogen, and phosphorus atoms. They are found in the nucleus of cells and are responsible for storing and transmitting genetic information.
In conclusion, the correct answer is A. Proteins.