Human beings everywhere have essentially the same biological constitution, yet their paths through the life span are remarkably different depending on .

Their culture

Explanation:

Culture is the total pattern of customs, ideas, beliefs, art, and technology of a particular group of people or society. It distinguishes the paths through life span of human beings despite having essentially the same biological constitution. It is the way of life of a particular group of people, that is socially transmitted from generation to generation

The correct option is b

Explanation:

Phospholipids are lipids that contains a phosphate group, which forms the "head" of the molecule and is hydrophilic (water loving). The "tail" of phospholipids is made of two fatty acids which are hydrophobic (water fearing). The phospholipid in the cell membrane acts as a selectively permeable barrier that regulates what goes in and out of the cell thereby protecting the cell from some external molecules and ions.