Why are lymph nodes considered secondary lymphoid tissue? Lymph nodes produce white blood cells, but they do not use white blood cells to fight infection.
Lymph nodes use white blood cells to fight infection, but they do not produce white blood cells.
Lymph nodes are the second line of defense against infection.
Lymph nodes are produced by the primary lymphoid tissues.

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