Chemical Reactions in Human Body Passage

Read the passage and answer the question that follows:

The human body is nothing but a set of chemical reactions in some form or the other. The religious scriptures believe that man was made out of the image of the creator of the universe. Does this mean that Oxygen was pumped into the human body and carbon dioxide pumped out to create this being? Is life just the process of oxygenation and decarburization? If the human body is managed by these two processes, then we can safely believe that life came into existence due to these chemical reactions. The highly complex chemicals compounds present in the human body are not evident in lower animals or plants. These substances were born because of the synthesis of other smaller molecules.

A large number of recognized chemicals has been observed and proved to be involved in the transmission of impulses from one tissue or cell to another. Some examples of such chemicals are adrenaline, dopamine, acetylcholine, endorphins and encephalin. The increase or decrease of any one of these chemicals, interferes with the normal functioning of cells and tissues. This creates diseases in the body, and the restoration of their supply cures the diseases. The deficiency of acetylcholine leads to Alzheimer's disease, while a decrease in dopamine leads to Parkinson's disease and its increase causes schizophrenia, a mental disorder. Endorphins and encephalon work like a drug to produce sensations like pleasure and reduce pain. In depressed persons, lower levels of serotonin and adrenaline are observed. Exercise and meditation help release endorphins in order to produce a sense of calmness and pleasure. As for love, the brain releases a chemical substance called phenyl ethylene which acts like an amphetamine to increase mental alertness and physical energy. People with low levels of these chemicals develop a craving for foods such as chocolates, which are rich in such compounds.

Which one of the words given below can be used in place of 'a mental disorder' as used in the passage?

Which one of these words is the right synonym for 'synthesis' as used in the passage:

Which one of the words given below is the right antonym for 'alertness' as used in the passage?