What two mechanisms on a microscope allow you to control the amount of light that hits your slide?

Condenser and Iris Diaphragm.

Explanation:

The working principle of a microscope is projecting a light source on the specimen that is being investigated under the lens. The two mechanisms that control the light, it's focus and it's amount on a microscope and for other lens-operated mechanisms such as telescopes as well, are the condenser and the iris diaphragm.

I hope this answer helps.

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.

any abiotic or biotic factor in an ecosystem that causes a population's size to slow or decrease is a limiting factor.