Final answer:
The valve that allows blood flow from the right atrium into the right ventricle is called the tricuspid valve.
Step-by-step explanation:
The valve that allows blood flow from the right atrium into the right ventricle is called the tricuspid valve. It is a one-way valve that prevents the backflow of blood. Other valves in the heart include the mitral valve (between the left atrium and left ventricle), pulmonary valve (between the right ventricle and pulmonary artery), and aortic valve (between the left ventricle and aorta).