Overproduction
Most species produce more offspring than can survive.
Competition
Since living space and food are limited, organisms must compete for the necessities.
Variation
Differences between individuals in a population.
Adaptations
Any kind of inherited trait that improves an organism's chances of survival.
Natural selection
The environment selects organisms with optimal traits to be the parents of the next generation.
Speciation
Over many generations, favorable adaptations accumulate and may result in a new species.
Vacuole. Amoeba is a unicellular organism formerly grouped under Kingdom Protista. Amoeba in freshwater need contractile vacuole to control input and output of water. (osmosis). Without this structure, ameboid cells will be filled with water and eventually burst.
The answer is nitrogen fixation.
Hope this helps
Answer:
The idea of concentrations and gradients within them is important when understanding the movement of substances across cell membranes. The more particles there are in a certain volume, the more concentrated those particles are. A solution with a low solute concentration has a high water concentration, and a high water potential.