Biological membranes are present in all cells, and they make up the endomembrane system of eukaryotic cells. Among other functions, they act as barriers that selectively allow the transport of small molecules and ions into and out of the cell or organelle. A) Which of the following best describes a biological membrane?1) a bilayer containing lipids with hydrophilic head groups pointing inward and hydrophobic tail groups oriented toward the solvent (extracellular fluid and cytosol)2) a bilayer containing lipids with hydrophilic head groups oriented toward the solvent (extracellular fluid and cytosol) and hydrophobic tail groups pointing inward3) a bilayer containing lipids with hydrophobic head groups oriented toward the solvent (extracellular fluid and cytosol) and hydrophilic tail groups pointing inwardB) Which of the following are components of biological membranes? Select all that apply.1) proteins2) nucleic acid3) proteins