Which describes primary succession, but not secondary succession? a. Small trees and shrubs replace grasses and other small plants.
b. Large trees replace small trees and shrubs.
c. The process often begins on lifeless, barren rocks that form from a
volcanic eruption
d. The process often begins after a human disturbance, such as clear-cutting a
forest

Which disturbance would result in primary succession?

harvesting wheat by using a combine harvester at the end of the growing season

controlled burning to stimulate the growth of forest trees such as sequoia

the formation of Surtsey, a volcanic island off of the southern coast of Iceland **

the effect of a large herd of elephants on the grasses and shrubs in an area

Explanation:

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.