Answer:
This is what I found. So if you use this please reword it as your own.
Explanation:
Have a great summer
Answer:
Organism.
Explanation:
The cell is the smallest form of life. Cells work together to form tissues, tissues work together to form organs, and organs work together to create an organ system, and organ systems work together to create organisms. I believe "organism" includes all of these other levels.
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.
