The number of species on Earth tagged at 8.7 million as of 2011.
A closed system is a system that makes no physical or chemical exchanges with its environment. Of these systems provided as choices (tree, human, clock, car), only a clock does not make exchanges with the environment, except for energy.
Therefore, of that list, only a clock would be a closed system.
Hope that helped! =)
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.
The situation that a new technology would be most likely to cause change in existing theory about cell is : D. The technology allows detection of a substance that could not be detected previously
Cell is incredibly small and we still hasn't 100% figured out their perfect mechanism yet. New technology might found the new substance that alter the cell's theory as a whole
hope this helps
Answer:
Again keeping with the similarity to the centromere, this metaphor also has been used to describe the building of the kinetochore on the centromere (56). DNA replication is regulated in the cell cycle in the following manner (Figure 1b): ORC recognizes and binds to the origin.
Explanation:
