Agroup of scientists is studying the internal parts of the cell. which microscope is most appropriate for these scientists to use?

Transmission Electron Microscope (TEM)

Explanation:

Transmission electron microscope (TEM) is the most appropriate microscope to visualize internal parts of the cell because it produces a very high resolution and magnified picture of internal parts. The magnification power of a TEM is upto 50 million whereas the resolution power of TEM is 0.5 Å.    

For TEM analysis, the samples are prepared on a carbon film coated grid. The image which is produced in TEM is due to unscattered electrons and elastically scattered electrons while inelastically scattered electrons do not play any role in forming image.

the oxygenated blood then leaves the lungs through pulmonary veins, which return it to the left heart, completing the pulmonary cycle. this blood then enters the left atrium, which pumps it through the mitral valve into the left ventricle. from the left ventricle, the blood passes through the aortic valve to the aorta.

deoxygenated blood leaves through the right ventricle through the pulmonary artery. from the right atrium, the blood is pumped through the tricuspid valve (or right atrioventricular valve), into the right ventricle.

the endomembrane system i think