Answer:
The valves' main job is to keep the blood moving in one direction – back up towards the heart. When the valve is open, blood freely flows upward towards the heart and when the valves are closed, blood cannot flow back
The liver is the biggest organ in your body
cell wall
the main difference between animal cell and plant cell is in existing of cell wall on plant cell and existing of centriols in animal cell large vacules in plant cell ...
By the sexual combs, the flies of the male fruits have a structure similar to a brush comb near their hind legs.