Which structure(s) carry oxygen-rich blood away from the heart?

The correct answer is arteries.

Explanation:

The arteries are the blood vessels that carry the blood away from the heart. In general, the arteries carry oxygen rich blood to the tissues present in the body. from the arteries the blood is transferred to the capillaries, from the exchange of gases between blood and tissues take place. The blood in capillary after delivering oxygen and up taking carbon dioxide is transferred to the veins and oxygen deficient blood is carried back to the heart.

The pulmonary artery and pulmonary vein are exceptions. The pulmonary artery carry deoxygenated blood from the heart to lungs, whereas, the pulmonary vein carry oxygenated blood to the heart.  

the level of progesterone is low at the pre-ovulatory phase of the cycle but it gradually increases and the levels are high at the luteal phase. if pregnancy occurs, the level of progesterone will be high throughout the pregnancy.

if egg is fertilized and the mother gets pregnant, progesterone starts preparing the uterus for the implantation. it starts building up the lining of uterus and make it hostile of the period of pregnancy.