Active transport requires energy because it usually involves the movement of
A.
substances from an area of low concentration to an area of high concentration.
B.
substances that can easily pass through the cell membrane, such as water.
C.
substances from an area of high concentration to an area of low concentration.
D.
substances in the gas phase, such as oxygen and carbon dioxide.
A. substances from an area of low concentration to an area of high concentration.
There are two main ways in which molecules are transported into and out of cells: active transport and passive transport. Which of the following is an example of active transport?
A.
filtration
B.
plasmolysis
C.
sodium-potassium pump
D.
osmosis