[单选题]
The important properties of animal cell membranes are fluidity and permeabc :hqlu40uaz5 1ab)dv 5.ei rwilityy9zv3 l1yc)x pyf5k(ar8/ xrm. Which molecule is responsible for ensuring 5x(/c1ryzra9 m38 ) plkxfyyvthe membrane’s fluidity?
A. Cholesterol
B. Integral Membrane Proteins
C. Glycolipids
D. Peripheral Membrane Proteins