False.
The semilunar valves are the pulmomic and aortic values.
the mitral and tricuspid valves prevent back flow of blood into the atria.
DNA themselves discovered DNA
JK
The molecule now known as DNA was first identified in the 1860s by a Swiss chemist called <span>Johann Friedrich Miescher</span>
1. wear safety glasses
2.never touch heating source
3. keep away from overhead shelving