Final answer:
Each rescue breath during rescue breathing should be given over a period of 1 second to effectively provide air to the lungs without causing injury.
Step-by-step explanation:
During rescue breathing, each breath should be given over 1 second. This involves delivering enough air to make the victim's chest rise, which typically takes about one second. It's crucial to not breathe too quickly or with too much force to avoid causing injury or discomfort. An effective rescue breath is one that introduces enough air into the lungs to provide oxygen to the body while simulating natural breathing patterns.