Which of these is an example of active transport?
Facilitated diffusion of K+
1. Transport of Cl- following its concentration gradient
2. Transport of Na+ from a place of low concentration to a place of higher concentration
3. Transport of glucose down its concentration gradient
4. Diffusion of oxygen from a place of high concentration to a place of lower concentration
5 Diffusion of oxygen from a place of high concentration to a place of lower concentration