What are some examples of passive transport?

What are examples active transport?

• I need 3 examples of active transport and I can't figure out any other examples other then plants using it to get nutrients from soil into its roots.

• Answer:

  One would be the use of the sodium potassium pump to make a concentration gradient that allows glucose and sodium to enter enterocytes (cells of the internal mucosal lining of the small intestine) in favor of given gradient. The pump uses energy in the form of ATP, the entrance of glucose and sodium is done through a channel, and as the entrance of sodium helps glucose enter, this transport is called "simport". Another example would be the ABC pump superfamily, which transports phospholipids and lipophillic substances through eucaryotic membranes. (The function is different in prokaryotes such as bacteria, these use the ABC pump to move aminoacids)