18) E, B, C, A, D

It is essential that you know the direction of blood flow and the order of blood vessels that it flows in.

Of course, ADH travels in blood.

I will use a flow chart to show exactly how the ADH will reach the kidney.

Pituitary Gland → Jugular Vein → Vena Cava → Right Atrium → Right Ventricle → Pulmonary Artery → Lungs → Pulmonary Vein → Left Atrium → Left Ventricle → Aorta → Renal Artery → Kidney