<span>Basically, the body needs to know what it is defending against. Your body can still (usually) fight off infection, even without an immunization, but it takes longer. Basically, your body creates cells with a receptor for a specific disease. When this cell finds the disease it is programmed for, it will send out signals to the "killer" cells to come and kill it. If your body doesn't have the "seeker" cells, it can't fight off the infection until it does. The opposite end are autoimmune diseases, where your immune system starts attacking itself.
brainlest answer</span>
Answer:
B. Hardness
Explanation:
Physical properties of a substance is defined as the properties which can be observed or measured without changing the composition of matter.
Physical properties include odor, appearance, color, texture, boiling point, melting point and many others.
Hardness is a physical property of a substance as it describes the resistance of substance to deformation and can be observed by simple touch or without changing the composition of matter.
While reactivity, toxicity and flammability are chemical properties of substances that change one type of matter into another type.
Hence, the correct option is B.
Antibodies- I hope that helps :)