How much you respect and like yourself
Larry is taking a walk in the park. The pollen in the air makes him sneeze constantly. The line of defense that is his immune system exhibiting is that of "(A) first line of defense." There are only 3 lines of defense in the immune system. The first line of defense are a combination of physical and chemical barriers that prevent all types of foreign agents from penetrating the outer layer of the body. In this case, it is the nasal cavity.
The answer among the choices is letter A. Sterols is a lipid that doesn't contain a glycerol backbone because it is mostly unsaturated. It can be commonly found on fungi, plants, and animals as an important organic molecule. I hope my answer helps you.
The type of immunity that uses both helper and killer cells is Cellular Immunity. It is used by Cellular immunity to classify the abnormal cells. Once abnormal cells are detected it is destroyed by Cellular Immunity. Cellular Immunity serve as resistance from diseases caused by viruses.