In an animal cell, the interior layer of the cell membrane (the H-C tails) is which of the following? O impermeable to all ions
O hydrophobic
O hydrophilic
O permeable to all ions

Hydrophobic

Explanation:

The structure of a cell membrane is that of a lipid bilayer consisting of a hydrophilic polar head and a hydrophobic (literally meaning water-hating) hydrocarbon tail.

The hydrophilic head group is a polar group, for example a sugar or choline  molecule.

The hydrophobic tail consists of two fatty acid chains of between 14 - 24 carbons  atoms. However, the most common fatty acids chains are those having 16 and 18 carbon atoms. Links in the tail arise if the carbon chain contains a cis- double bond. This serves to reduce the tight packing of the membrane and so increases membrane fluidity.  The hydrocarbon tails are hydrophobic and non-polar and therefore do not form hydrogen bonds with water.

The overall function of the cell membrane is to serve as a selective barrier between the cell and its environment.

the cell theory states that all living things including animals, as well as plants, are made of cells.

✿   this landform has a high elevation and a high relief

✿   this landform is a mountain