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The antigen-antibody immunological reaction is used to be regarded as typical of immunological responses. Antibodies are proteins synthesized by specialized cells called plasma cells, which are formed by lymphocytes (cells from the lymph system) when an antigen, a substance foreign to an organism's body, comes in contact with lymphocytes. Two important manifestations of antigen-antibody immunity are lysis, the rapid physical rupture of antigenic cells and the liberation of their contents into the surrounding medium, and phagocytosis, a process in which antigenic particles are engulfed by and very often digested by macrophages and polymorphs. The process of lysis is executed by a complex and unstable blood constituent known as complement, which will not work unless it is activated by a specific antibody; the process of phagocytosis is greatly facilitated when the particles to be engulfed are coated by a specific antibody directed against them.

What happens when an antigen comes in contact with lymphocytes?

The renal medulla is composed of tissue called

In the following question, out of the four alternatives, select the alternative which is the best substitute of the phrase.

The punishment of being kept in school after hours.

Choose the word that best defines the given phrase‘Prolonged inability to sleep’

In the following question, the sentence given with blank to be filled in with an appropriate word. Select the correct alternative out of the four and indicate it by selecting the appropriate option.
 
She does not agree, and ______ does Anita

The longest bone in the human body is

Electric power is measured in units of

A duty is a task required of which citizens