How can water erosion by groundwater form a cave?

Water sinks into the ground and mixes with carbon dioxide to form carbonic acid. Carbon acid can break down limestone. Some of the limestone gets carried away.

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.

the second type of galaxy is called a barred spiral, which has a thing called a bar straddling the nucleus