The skin contains a precursor to vitamin D that, when activated, allows for which action?

Pulmonary vein. This is because the pulmonary vein is the only vessel that carries oxygenated blood from the lungs to the heart. The blood then enters the left atrium of the heart and then the left ventricle.

Choice B. Inferior vena cava is wrong because it carries deoxygenated blood from the lower body to the right atrium of the heart.

Choice C. Aorta is wrong because it carries oxygenated blood from the left ventricle of the heart to the rest of the body.

Choice D. Pulmonary artery is wrong because it carries deoxygenated blood from the right ventricle of the heart to the lungs.

Carry oxygen. Hemoglobin is an iron-containing protein in red blood cells that transports oxygen from the lungs to the tissues and carbon dioxide from the cells to the lungs. Hemoglobin has four heme groups that can bind one oxygen molecule each.

Choice A is wrong because hemoglobin does not produce blood clots. Blood clotting is a process that involves platelets, fibrin and other factors.

Choice B is wrong because hemoglobin does not transport hormones. Hormones are chemical messengers that are carried by the blood plasma or bound to specific carrier proteins.

Choice C is wrong because hemoglobin does not fight infection. Infection is fought by white blood cells and antibodies.

The tibialis anterior muscle is located in the lower leg, on the lateral side of the tibia.

It originates from the lateral condyle and surface of the tibia and the interosseous membrane, and inserts into the medial cuneiform and first metatarsal bones of the foot. It acts to dorsiflex and invert the foot.

Choice A is wrong because the upper arm does not contain the tibialis anterior muscle.

The upper arm contains muscles such as biceps brachii, triceps brachii, and brachialis.

Choice C is wrong because the thigh does not contain the tibialis anterior muscle.

The thigh contains muscles such as quadriceps femoris, hamstrings, and adductors.

Choice D is wrong because the abdomen does not contain the tibialis anterior muscle.

The abdomen contains muscles such as rectus abdominis, obliques, and transversus abdominis.

Diaphysis. The diaphysis is the tubular shaft that runs between the proximal and distal ends of the bone. The distal region of the humerus is the lower area of the humerus that is closest to the elbow.

Therefore, a fracture in the distal region of the humerus would affect the diaphysis.

Choice A is wrong because epiphysis is the wider section at each end of the bone that is filled with spongy bone.

The epiphysis is not part of the shaft of the bone.

Choice B is wrong because endosteum is the delicate membranous lining of the medullary cavity, where bone growth, repair, and remodeling occur.

The endosteum is not a region of the bone, but a tissue that lines the inner surface.

Choice C is wrong because perichondrium is a layer of dense irregular connective tissue that surrounds the cartilage of developing bone.

The perichondrium is not a part of the bone itself, but a covering that helps with nourishment and growth.