In simple diffusion, small molecules without charges such as oxygen and carbon dioxide flow through a plasma membrane without assistance and without expending energy. Other substances such as proteins<span>, glucose and charged particles called ions cannot pass through the selectively permeable membrane.</span>
The answer to this question would be: electron
When atoms bind together, that mean they shared at least one electron. The electron is located on the outer side of the atoms so the electron from an atom can collide with other electrons from another atom. The protons and neutron can't make bind because it was in the middle of the atom and won't collide each other.
What about it?? What’s the question?
