Final answer:
Edema can be caused by venous constriction, which increases pressure and fluid flow out of capillaries, and by a loss of plasma proteins like albumin, leading to decreased colloid osmotic pressure and fluid leakage into tissues. Arteriolar constriction and dehydration are less likely to cause edema.
Step-by-step explanation:
From the options provided, two factors that can lead to edema are venous constriction and loss of protein from the body. Venous constriction can lead to an increase in blood pressure within the veins. When there's increased pressure, it promotes the flow of fluids out of the capillaries and into the surrounding tissues, causing edema. Loss of protein, specifically a decrease in the levels of plasma proteins like albumin, results in a drop in colloid osmotic pressure. Albumin normally helps to maintain the water content of the tissues, so with lower levels of albumin, there is more water leakage from the blood into tissues, also resulting in edema.
On the other hand, arteriolar constriction would actually lead to decreased blood flow to the area past the constriction, not necessarily causing edema, and dehydration is more likely to reduce tissue fluid volume, counteracting edema.