The phospholipid by layer is What

Phospholipids are made up of two layers, the outer and inner layers. The inside layer is made of hydrophobic fatty acid tails, while the outer layer is made up of hydrophilic polar heads that are pointed toward the water.

the most common type of reef is the fringing reef. this type of reef grows seaward directly from the shore. they form borders along the shoreline and surrounding islands.