In facilitated diffusion, proteins provide openings in the plasma membrane for substances to flow through without changing structure, and proteins allow passage of substances through the plasma membrane after undergoing a subtle change in shape.

CHANNEL PROTEINS provide openings in the plasma membrane for substances to flow through without changing structure, and CARRIER PROTEINS allow passage of substances through the plasma membrane after undergoing a subtle change in shape.

Explanation: They are described thus:

A channel protein is a protein that allows the transport of specific substances across a cell membrane.

Carrier proteins are proteins that carry substances from one side of a biological membrane to the other. Many carrier proteins are found in a cell’s membrane, though they may also be found in the membranes of internal organelles such as the mitochondria, chloroplasts, nucleolus, and others.

maybe because its impossible for balloons to lift a whole entire house.