Which of the following processes requires membrane proteins?

Which of the following statements is correct?
$(I)$ Rapid uptake of ions into the free space is a passive process.
$(II)$ Apoplast is important for passive processes.
$(III)$ Metabolic energy is required in passive processes.
$(IV)$ In the apoplast,passive processes occur through ion channels.

Movement among cells against concentration gradient is called

Active transport of ions by the cell requires

Transport occurs against the concentration gradient.

Water channels are