Evaluation of an infant reveals hypocalcemia due to a lack of parathyroid hormone. On x-ray, the thymic shadow is absent. Which of the following embryonic structures is involved

Anatomy

Evaluation of an infant reveals hypocalcemia due to a lack of parathyroid hormone. On x-ray, the thymic shadow is absent. Which of the following embryonic structures is involved

The action of digastric muscle is:

Which of the following vessels supply the anal canal?

All of the following muscles are elevators of the mandible EXCEPT: