Natural selection :) In simple terms in the one with the best traits will repopulate so they can have the best traits the individuals who are weak typically die off and no one breeds with them :)
Answer:
An ECG technician operates a machine that produces visible waves of electrical heart activity.
Explanation:
Hope it helps you
Mark my answer as brainlist
have a good day
Uhh normally they mean that the person is unaffected or a carrier, but you'd have to look at a specific one since some have different keys.
So basically, my best advice would be to look up some sort of site that makes DNA strands and base it off of one of those. I Forgot how to do the rest but maybe somebody else can help
hope it helps -_-