A phospholipid is comprised of a phosphate hydrophilic head, which means that it is "water-loving," and a fatty acid hydrophobic tail, which is "water-hating." The head and the tail are joined together by a glycerol molecule. The phosphate head is attracted to water because it is charged (i.e. negatively). Water is a polar molecule, which means that there is an uneven distribution of charges within its molecular structure with the oxygen side being "more negative" than the rest of the atom (which is "more positive" near the hydrogen). Thus, the negatively-charged nature of the phosphate head and the parts of the water molecule which are positively charged enable the two to form an "attraction" towards one another.
On the other hand, the hydrophobic tail is nonpolar, which means that it does not have a "more positive" or "more negative" side or part in its molecular structure. These differences in structure with water make the hydrophobic tail unattracted to water molecules and more attracted to other uncharged, nonpolar molecules (such as fats and oils).
D. One sex has a higher chance to inherit it than the other (male).
These can be either recessive or dominant. We usually think more of the recessive traits like color blindness and hemophilia but dominant sex-linked traits also exist (fragile X).
The barnacles are only able to attach them selfs to surfaces in the water. Since the surface is limited, barnacles are attaching themselves to the other barnacles, crowding the rock. The muscles were not able to grow or attach themselves off the surface of the rock. Same thing with the mussels that are growing on the rock. So not only barnacles are crowding the rock, but Mussels as well are crowding the rock.
