The principal excitatory neurotransmitter 1. Especially involved in learning and memory.2. Involved in dependency and addiction, and might play a role in many other disorders such as major depressive disorder. 3. Too much can overstimulate the brain and trigger migraines or even seizures.

The answers are 1)Especially involved in learning and memory and 3)Too much can overstimulate the brain and trigger migraines or even seizures.

Explanation:

Glutamate is closely related to the learning and memory process. During learning, glutamate levels increase, suggesting that this compound plays a very important role during the learning process. Glutamate is essential for memory and recovery. This neurotransmitter participates in the synapse in the brain and its excess is harmful to neurons and is related to diseases such as migraine.

answer; i believe the correct answer is (data); /// good luck

b. the carbon cycle ensures living things have a source of hydrogen