The leaked fluid is being absorbed by pathogens and dead cells, so when the fluid is returned to the blood, the body can stabilize its internal conditions (homeostasis.)
D is the answer due to lack of knowledge and accessibility
Random sampling means that members of a 'population' have equal chances of being selected. To carry out this type of sampling, you will need to use a table of random numbers.
There are three kinds of blood vessels: arteries, veins, and capillaries. Each of these plays a very specific role in the circulation process. Arteries carry oxygenated blood away from the heart. They're tough on the outside but they contain a smooth interior layer of epithelial cells that allows blood to flow easily.