1. are physical barriers that
prevent microorganisms from gaining en-
try or expel microorganisms before they
multiply. (Mechanical defense mechanisms,
Chemical defense mechanisms, Electrical defense
mechanisms)

True or false a fertilized cell divides many times to form an embryo

Mason joined the water polo team at his school. as part of his conditioning, mason's coach requires a 25-minute run during practice. mason's heart rate reaches 125 beats per minute, but his target heart rate zone is 138—183 beats per minute. what should mason do to get the most benefit for his heart? increase the amount of time he runs increase the speed at which he runs decrease the amount of time he runs decrease the speed at which he runs

Second hand smoke can be almost as harmful as smoking. true or false?