Apsidal precession—The major axis of Moon's elliptical orbit rotates by one complete revolution once every 8.85 years in the same direction as the Moon's rotation itself.
solution:
You need to find the frequency, and they have already given you the wavelength. And since you already know the speed of light, you can use formula (2) to answer this problem. Remember to convert the nano meters to meters because the speed of light is in meters. 

Answer:
The answer is: phospholipid molecules
Explanation:
The plasma membrane of a cell is consists of a lipid bilayer. This lipid bilayer, also known as the phospholipid bilayer, is a polar membrane composed of two layers of lipid molecules, usually amphipathic phospholipid molecules.
The amphipathic phospholipid molecules have a hydrophilic phosphate head on the exterior and a hydrophobic tail consisting of fatty acid chain on the interior of the membrane.
La respuestas de lo que descirbiste es 18.02 gramos
Saludos
A mixture called a solution, I think.