Final answer:
The thoracic cavity holds the heart, situated in the pericardial cavity. The other options listed, such as the ovaries, uterus, and brain, are located in different cavities, not the thoracic cavity.
Step-by-step explanation:
The thoracic cavity is a key area within the ventral cavity and is protected by the thoracic cage, commonly known as the ribcage. This cavity is divided into the pleural cavities, which each contain a lung, and the pericardial cavity, which contains the heart. Based on these distinctions, the correct answer to the question, 'The thoracic cavity holds which of the following organs?', is D. Heart. The ovaries and uterus are located in the pelvic cavity, and the brain is in the cranial cavity, which is part of the dorsal body cavity, not the thoracic cavity.