Final answer:
The gland located in front of the lower voice box and the upper trachea, shaped like a shield, and the largest endocrine gland is the thyroid gland.
Step-by-step explanation:
Located in front of the lower voice box (larynx) and the upper trachea, the thyroid gland is the largest endocrine gland and is shaped like a shield. The correct answer to the quiz question is c) Thyroid. This gland is butterfly-shaped, situated in the neck beneath the larynx and wraps around the trachea. The thyroid gland is responsible for producing three key hormones: thyroxine (T4), triiodothyronine (T3), and calcitonin. These hormones play a crucial role in regulating metabolism and calcium levels in the blood. The parathyroid glands, which help regulate calcium in the body, are embedded in the posterior surface of the thyroid gland.