Why are lipids able to function as protective barriers in cells?

The reason behind the lipids which are able to function as protective barriers in cells is that lipids do not dissolve in water.
If lipids dissolve in water, they will not be able to function as protective barriers in cells. Nucleic acids, proteins, lipids and carbohydrates are the four types of macro-molecules in the cell.

If these are the missing choices: a. to determine skin temperature, place the back of your hand against the patient's skin.b. determine body temperature by touching the patient's hands and feet.c. skin temperature will tell you very little about this patient's condition or well-being.d. the patient's skin temperature and color will likely be warm and red.my answer is: a. to determine skin temperature, place the back of your hand against the patient's skin. using the back of the hand to check for temperature rather than the palm is more effective because the back of the hand has more nerves that can feel and transmit the temperature than the palm.