Question

what is vaccine ? ncert class 8th science ​

Answer 1

Answer:

A dose of dead and disease causing microbes is called vaccine.

When vaccine is introduced in the body of a healthy person is acts like antigen. The body of the person releases antibodies against these introduced microbes. These antibodies remains in the body of that person and protect from future infections.

Answer 2

Answer:

A vaccine is a biological preparation that improves immunity to a particular disease by producing antibodies against the disease causing microbes.

A vaccine contains an extract of the disease causing micro organism, and is made from weakened forms of the microbe.

The weakened form or the microbe is used to get the response from the body so that when the real disease causing microbes enter the body, the body is almost ready for defence.

There are many diseases against which vaccines can be used for protection, example - cholera, tuberculosis, and hepatitis.