it is a.cell because tissues, organs and organisms are larger than a cell so 'a' is the correct answer
Osmosis. If the cell has too much salt the cells will swell. let me know if you want me to explain.
There are other types of selection, in addition to natural selection, that are out there in the world. Think about some decisions you make about the types of pets you want or what kind of foods you prefer to eat. Artificial selection, also called "selective breeding”, is where humans select for desirable traits in agricultural products or animals, rather than leaving the species to evolve and change gradually without human interference, like in natural selection.