What does the word resources mean as it is used in the passage? Environmental scientists pay attention to rapidly rising populations of animals in a region. While the increase in the number of animals might seem to indicate a positive change in the environment, rising lead to concerns about carrying capacity and resources available to a population.
a various supplies of wealth
b places where information is obtained
c inborn abilities to handle different situations
d natural objects useful for survival

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.

condenser is used to focus in the light microscope.