Search it up on google and you will find the answers there
Your answer would most likely be (c) or the third answer given.
Antigens are proteins that are found on the surface of the pathogen and are viruses, fungi, or bacteria. Nonliving substances such as toxins, chemicals, drugs, and foreign particles. Antigens are usually carried by proteins and polysaccharides, and less frequently, lipids but it also needs to be attached to a large carrier molecule which is usually a protein. When an antigen enters the body, the immune system produces antibodies against it. The Antigen stimulates the immune system to produce antibodies. YOUR WELCOME ;)
In doing these exercises, this is likely to increase the response of the parasympathetic nervous system in which results of making the heart slow and as well as the respiration rate with less muscular tension. The parasympathetic nervous system is the one responsible for conserving energy that makes the heart rate slower, increase the activity of the gland and intestinal activity and as well as relaxing the muscles.