Synapses are able to change strength and function when a pathway is stressed, overused, or underused, such as by the intake of psychoactive substances

This is a true statement.
This statement describes a very important ability of the synapses called synaptic plasticity. These changes can last from weeks to years and it has been observed that the younger the user the more probable that the changes will remain. This is the reason that some chronic users find it very difficult to recover from the drug abuse.

Water's unique properties

In the solid state, the particles of matter are usually much closer together than they are in the liquid state. So if you put a solid into its corresponding liquid, it sinks. Water's boiling point is unusually high. Other compounds similar in weight to water have a much lower boiling point.

Explanation: