Which molecule would require a channel or a transport protein to cross the cell membrane

those molecules which are not lipid in nature and the uncharged substance such as oxygen carbon dioxide can move through the membrane without the help of transport protein

WHAT SUBSTANCES NEED HELP OF TRANSPORT PROTEIN

Ions, sugars, amino acids, and sometimes water cannot diffuse across the phospholipids

the transfer of energy between two molecules spaced just nanometers apart plays a key role in many technologies, including photovoltaics, quantum information systems, lighting, and sensors, as well as in biophysics to measure nanometer distances and in photosynthesis. but an open question in this area is what effect, if any, the surrounding photonic environment has on this nanoscale energy transfer. by designing and performing a carefully controlled experiment to answer this question, scientists have settled the debate and found clues to improving the efficiency of many of the technologies that rely on this process.

explanation:

they deliver oxygen to the blood