Plasma is the
fibers in blood
matrix of blood
cell that phagocytizes bacteria
cell fragment found in the tissue

Matrix of blood

Explanation:

Plasma is known as the upper phase, obtained after centrifugation of the blood. It is essentially the matrix of the blood: water, sugars, salts and small proteins. The rest of the larger components, such as platelets, red and white blood cells will remain in the lower phases, depending on their size and mass.

thermophiles, notice the prefix thermo.

if the type of the food available changes, then the frequency of beak types will change, because birds with beaks more suited to the available food will be more successful over time.