Answer:
Answer: Option D.
Step-by-step explanation:
Step-by-step explanation:
Active transport is defined as the movement of solutes or molecules across a membrane on the basis of difference in solute concentration.
Active transport functions continuously due to diffusion that allows solutes to move constantly across the membrane. Cells have low concentrations of sodium (Na+) and high concentrations of potassium (K+). Hence, the electrical gradient and concentration gradient of sodium (Na+) that allows diffusion of the ion into the cell, and the electrical gradient of Na+ (a positive ion) that allows movement of ion inward to the negatively charged interior.
Hence, the correct option is D.