<span>Depression is linked to an imbalanced level in serotonin. Serotonin is a neurotransmitter that is produced in the brain. These neurotransmitters helps the brain to send and receive messages from one part of the body to another. Serotonin affects nearly all the cells within the brain. As a result human behavior, mood, sleep, and even appetite can be greatly influenced. Aggressive behavior although can result from the same imbalanced levels of serotonin. Researches believe that the lack of receptors, or the inability for serotonin to reach these receptors, may also impact our ability to control anger and aggression.</span>
Answer:
The correct answer is : trained skeletal muscles
Explanation:
Physical training helps and induces adaptive changes in skeletal muscle. The change that is the most notable one is the increased concentrations of mitochondria and glycogen. The longer the training you do and the harder, the major changes in metabolism are presented.
The more Carbon Dioxide in the air, the more it increases the GREENHOUSE EFFECT.