Phospholipids, molecules found within a cell membrane, have hydrophobic tails and hydrophilic heads. these regions act in the same manner that hydrophobic and hydrophilic amino acids act. when phospholipids are found as a sphere in a glass of water, which of the following would you expect?
a. the hydrophobic tails will point toward the water, and the hydrophilic heads will point away from the water.
b. the hydrophilic heads will point toward the water, and the hydrophobic tails will point away from the water.
c. hydrophilic heads and hydrophobic tails will both point toward the water.
d. the hydrophobic tails and hydrophilic heads will be arranged randomly.

B

Explanation:

When a phospholipid is found in a sphere of water, the hydrophilic head is expected to point towards the water while the hydrophobic tail will point away from the water.

The term hydrophilic means water loving, So it is expected that the hydrophilic head will move towards water molecules at it has affinity for water molecules.

The opposite is the case for the hydrophobic tail. The hydrophobic tail moves away from water molecules

What these cases suggest is that both regions are acting base on their chemical make up. While the hydrophilic head contains molecules which are capable of interacting and bonding with water molecules, the hydrophobic tail contains strictly non polar molecules which are not capable of water interaction. Hence the interactions a phospholipid has with water is through its head region

your answer is a. the enthalpy of formation for a pure element in its standard state is always positive.