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Answer:
An aphthous ulcer is an ulcer that forms on the mucous membranes. They are also called aphthae, aphthosis, aphthous stomatitis and canker sores. ... Recurrent aphthous ulcers are mostly a minor nuisance, but they are associated with significant health problems in some people.
The right ventricle pumps deoxygenated blood to the lungs where it absorbs oxygen.