The inability to start a pregnancy after having unprotected vaginal intercourse for more than a year or the inability to stay pregnant for the full length of a normal pregnancy

Your answer is  d.)relationship between pressure and air volume and led to the understanding of how respiration works

Answergoing for a brief walk ahead of time and stretching afterward;

Have a plan for where to go in an emergency, pack a bag with plenty of food and water stock regularly replacing expired food; pack flashlights,batteries, and a first aid kit. go over the plan with your family once a month, when disaster happens seek shelter and wait for .