Can your body make antibodies for pathogens that you have never been in contact with? why or why not

Yes. You can get many colds in a year or a lifetime and make antibodies for each. 

Yes,because it can get cold every year or a life time

People who utilizes the progression principle will ensure their exercise program increases in frequency, intensity, time, and type. the changes need to happen gradually in order to ensure they make gains in their fitness program. a person who doesn't utilize the progression principle can still gain health benefits from exercising, but will not continue to improve in cardiovascular fitness.