Substances like oxygen pass through the cell without the use of energy and move from an area of high concentration to an area of low concentration. this process is called what?

If a substance passes from an area of high concentration to an area of low concentration, it's called diffusion.

This process is known as diffusion.

Explanation:Diffusion is the movement of a substance from an area of high concentration to an area of low concentration. It happens in liquids and gases because their particles move randomly from place to place.It does not require energy as it is a passive transport.According to above information the transport of oxygen in cells from high concentration to low concentration is diffusion.

Six amino acids have side chains that are polar but not charged. these are serine (ser), threonine (thr), cysteine (cys), asparagine (asn), glutamine (gln), and tyrosine (tyr). these amino acids are usually found at the surface of proteins, as discussed in the proteins 2 module.