Vaccines are effective because the body "remembers" the exposure to the vaccine's component, and can react swiftly to attack and destroy these components the next time they are encountered naturally in the environment. this occurs becauselymphocytes called "b cells" are activated by certain antigens, and, when combined with a chemical signal from t cells, divide rapidly to form two groups of many identical cells (clones). one group forms the active disease-fighting army of plasma cells, and secrete antibodies into the blood. the second group remains stored in lymph nodes, ready to develop rapidly into more plasma cells at the next exposure to the same antigen. what are these warrior cells, waiting in reserve in the lymph nodes, called?
a. cytotoxic cells
b. memory cells
c. macrophages
d. antibodies

Memory cells.

Explanation:

Vaccines are effective because they lead to the production of  memory cells which remembers the experience when the body got an exposure to the antigen for the first time.

When the antigen get exposed to the body, B cells of the body are activated. They further get divided into two parts, one part forms plasma cells and the other part forms memory cells.

The plasma cells secrete antibodies in the blood to fight disease and other part gets stored in the lymph until it is exposed for the second to antigen which will convert them into plasma cells.

The reserved cells are known as memory cells.

answer:

y for points : )

explanation:

answer:

thousands of years before the arrival of the british, australia was settled by the indigenous people of australia called the aborigines. this timeline begins when the europeans first arrived. 1606 - the first european to land at australia is dutch explorer captain willem janszoon.

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