Instructions Full Game: These are multiple-choice quizzes with four possible answer choices that include all questions in a given set.     
What part of the body fits the following description?
A large mass of gray matter in the dorsal part of the diencephalon of the brain with several functions such as relaying of sensory signals, including motor signals to the cerebral cortex, and the regulation of consciousness, sleep, and alertness.
thyroid gland
adrenal gland
parathyroid gland
thalamus