Final answer:
Active transport requires energy, usually ATP, to move nutrients across the cell membrane into the cell, depositing them into capillaries. This process is essential for maintaining various gradients and cellular functions.
The correct answer is a) Membrane.
Step-by-step explanation:
Active transport is the use of energy by absorptive cells to carry nutrients from one side of the cell membrane to the other, where they are deposited into capillaries.
Active transport utilizes energy, often in the form of adenosine triphosphate (ATP), to move substances across the plasma membrane from an area of lower concentration to an area of higher concentration. Proteins in the cell membrane act as "pumps", specifically moving materials against the concentration gradient. Two examples of active transport include the sodium-potassium pump and vesicular transport processes like endocytosis.