The structure that serves as the cell's boundaries from its environment is known as the CELL MEMBRANE. It keeps the bad things from coming in, and releases waste out into the environment.
<span>Answer: cell membrane</span>
<span>Colostrum
is replaced by transitional milk in about 2 to 4 days after birth. This milk
contains high levels of lactose, fat, vitamins and more calories than the
colostrum. Mature milk replaces the transitional milk and begins to appear near
the end of the second week after childbirth. Mature milk contains more water than
transitional milk.</span>
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