Suppose you had a bacterial sample of an unknown species. you perform a gram stain and observe purple rods. what can you conclude about the bacteria?

The answer is gram-positive

Gram staining could be used to know whether the microorganism is having a thick peptidoglycan layer or not. A thick layer of peptidoglycan will retain the crystal violet stain, make the microorganism become purple when observed using microscope. If the peptidoglycan is too thin, the color will fade and the bacteria will retain pink color from safranin.

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.