Why are phospholipids of the plasma membrane oriented such that their heads are at the membrane surfaces and their tails are buried in the interior of the membrane?

What is the best conclusion based on this data? the hypothesis was not supported because the data indicated that fertilizing plants does not improve plant growth. the hypothesis was supported; to get the best growth, use 5 milliliters of fertilizer per plant. the hypothesis was not supported; the data indicated that too much fertilizer can inhibit plant growth. the hypothesis was supported; to get the best growth, use 15 milliliters of fertilizer per plant.