Which cell structure is made of a bilayer of phospholipids and
encloses all cells?

The cell structure is the plasma membrane also known as the cell membrane.

Explanation:

The plasma membrane is the thin coat of lipids (phospholipids) that surrounds and encloses a cell, also can be called the cell membrane

answer///multiple alleles;

homeostasis is the tendency towards a relatively stable equilibrium between interdependent elements, especially as maintained by physiological processes. and this is how it applies to the integumentary system. back to top. skin functions in homeostasis include protection, regulation of body temperature, sensory reception, water balance, synthesis of vitamins and hormones, and absorption of materials. when body temperature falls, the sweat glands constrict and sweat production decreases.