The answer is B: the instructions for making some proteins are not specified by genes.
Cell membranes are made of many things, however, for your question,
Phospholipids make up the largest portion.
Proteins span and line the membrane.
Cholesterol can be found in the phospholipid bilayer.
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Point source means: the pollution that comes from a single point (examples)
Sewage pipes releasing sewage into a ditch
Smokestack style factory chimneys
Oil pipes
Pollution which is caused by rain fall or snow melting into the ground. As the runoff moves, it picks up and carries away natural and human made pollutants, Finally reaching a lake, river, ocean, groundwater.
<span>They become more dense at the outer portion of the convection currents</span>