In the following choices above, the letter which is not a property of water is letter A. Water is made of two hydrogen atoms and one oxygen atom combined in a weak ionic bond which breaks down easily. -- it is not a property of water because the ionic bond is strong and it will not cause to break down easily.
D- the mountains are evidence of plate tectonics
It moves scientific knowledge forward.
Answer:Valves stop blood flowing backwards
Explanation: Valve are flags of tissue that control the direction of the blood in our heart.,it prevent the backwards flow of blood. valves regulate blood from flowing back into the atria.The right and left atrio-ventricular valves prevent blood from flowing backwards into atria. When the ventricle is full,the valve prevent backwards flow of blood.
