Answer:
Primitive Earth where life emerged was subjected to extreme conditions
Explanation:
The origin of life is still an issue of intense debate today, although most researchers believe that life emerged from primitive organisms generated by the synthesis of organic compounds in early Earth. In line with this theory, it has been shown that membrane-forming compounds can be formed in extreme conditions (i.e., UV rays, extreme temperature, etc). It is believed that such conditions recreated in a laboratory were similar to the early Earth about 3,900 million years ago, thereby supporting the idea of the 'primordial soup theory' proposed by John Burdon Sanderson Haldane in 1929.
Answer:
Our immune system produces antibodies against that antigen of pathogen.
Explanation:
Injecting an antigen from a pathogen would help our immune system memorize the infection and protect our body from causing of the disease because our immune system produces antibodies against that antigen so when the pathogen enters our body these antibodies attack on that and prevent them of causing infection in the body so that's why injecting an antigen has to be done from the childhood to prevent diseases.