What are the two features of molecules that can undergo simple diffusion?

This type of diffusion proceeds without an input of energy. In simple diffusion, molecules that are small and uncharged can freely diffuse across a cell membrane. They simply flow through the cell membrane. Simple diffusion does not require energy or need the assistance of a transport protein.

Explanation:

simple diffusion is the process by which solutes are moved along a concentration gradient in a solution or across a semipermeable membrane. Simple diffusion is carried out by the actions of hydrogen bonds forming between water molecules and solutes. Water molecules move in to surround individual solute molecules, which maximizes hydrogen bonding. Hydrogen bonds are extremely temporary, however, and the solution is constantly stirred as a result.

Explanation:

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answer; the correct answer is (beta)

answer; ///(b) it is composed of four protein chains and four heme groups;