<span>Diffusion. Diffusion is when particles in a highly concentrated area spread out to an area of lower concentration. The membranes of cells are very thin, which allows diffusion of different materials to happen easily.
During respiration, oxygen and glucose concentration in the cell is lower than in the surrounding blood. This causes oxygen and glucose to move into the cell via diffusion. Carbon dioxide is produced inside the cell and this makes the concentration of CO2 higher in the cell than in the blood, so the excess diffuses out of the cell.</span>
Answer:
The correct answer is d. Oxygen
Explanation:
Phytoplanktons are responsible for the fixation of approximately half of the global carbon therefore seawater has high CO2 concentration which is required by phytoplanktons to make their food.
They are the primary producers of oceans and they are responsible to support the food chain of oceans. Factors that can limit their growth are mainly sunlight and nutrients like phosphorus, nitrogen, etc.
As phytoplanktons are photosynthetic they release oxygen itself as a byproduct therefore oxygen is not a limiting factor to phytoplanktons. So the right answer is d.
