I think the correct answer from the choices listed above is option A. It is the alveoli that is composed of single layer <span>surrounded by a network of capillaries. These are used to allow oxygen and carbon dioxide to move from the lungs to the bloodstream.</span>
I believe your answer is B, Because electrons are clinched to protons, most times, therefor there is not an electron microscope, but a ELECTRONIC Microscope will show the organism on a screen. hope that helped some<span />
