- A Passive transport
- B Active transport (primary)
- C Simple diffusion
- D Facilitated diffusion
Correct answer: B. Active transport (primary)
Explanation: The Na+/K+ ATPase pump transports 3 Na+ out and 2 K+ in per ATP, against concentration gradients: primary active transport.
Concept context
Cell theory, prokaryotic vs eukaryotic cells, organelles and their functions. Foundation of all biology.