How does your body have antigen receptors (either B cell receptors or T cell receptors) for antigens they have never encountered?

The answer is ozone layer.

When scientist examine data such as historical documents, they are using the "scientific methods"

This  focuses on  the entrepreneurial leadership of these  growth  firms.   governmentministers can play a critical  role  in  fostering  enterprise and innovation. their  role  is to direct thegovernment  departments and agencies to  focus  on the problem and develop effective policies.