Easy. Answer is oxygen because it says which one was missing before any life was on earth. And in order to have life on earth you need oxygen!
:)
The plasma membrane is the boundary between the cell and its environment. It regulates what enters and exits the cell. Cells must maintain an appropriate amount of molecules to function inside them. They must also have a way to keep things out or to allow things to enter. This is the job of the plasma membrane. The plasma membrane is like the guard at a gated community. The guard must inspect those who enter and those who leave to make sure that only the people and things needed in the community are there.
The cell membrane is a thin semi-permeable membrane that surrounds the cytoplasm of a cell. Its function is to protect the integrity of the interior of the cell by allowing certain substances into the cell, while keeping other substances out. It also serves as a base of attachment for the cytoskeleton in some organisms and the cell wall in others. Thus the cell membrane also serves to help support the cell and help maintain its shape.
If mitosis occurs correctly, the division of one cell by mitosis produces two cells.
Each vaccinated child stops the transmission of the disease. therefore, as long as 90 percent of the people in a community are immunized, no one dies of the disease.
<h3>What is herd immunity?</h3>
The expression herd immunity makes reference to a level of immunization in the population in which people become resistant to the pathogen.
In conclusion, each vaccinated child stops the transmission of the disease. therefore, as long as 90 percent of the people in a community are immunized, no one dies of the disease.
Learn more about herd immunity here:
brainly.com/question/18358089
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Corn is always in your
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