Lumen a. vessel that empties into the right atrium
O b. fibrous sac around the heart
O c. structure that keeps fluid moving forward
O d. central opening of a vessel
O e. lower, pointed region of the heart

Lumen corresponds to the central opening of a vessel (option d).

Explanation:

From the biological point of view, lumen is the internal space of any structure or tubular organ, whose purpose is the conduction of substances through it.

In the case of blood vessels, the lumen is a central space covered by a simple epithelium, called the endothelium, which ensures the passage of blood in a fluid form.

The other options do not correspond to the

    a. Vessel that empties into the right atrium is the vena cava

    b. Fibrous sac around the heart is the pericardium.

    c. Structure that keeps fluid moving forward, it is a blood vessel.

    e. Lower, pointed region of the heart, corresponds to the cardiac apex.

nope

explanation:

men

cheetos? that's the answer? ?