What does the prefrontal cortex do? what happens to grey matter in adolescence? what does this mean?

Adolescence is a time of significant growth and development inside the teenage brain. The main change is that unused connections in the thinking and processing part of your child's brain (called the grey matter) are 'pruned' away. ... The front part of the brain, the prefrontal cortex, is remodelled last.

the enthalpy of formation of water is given as -285.8kj/mol, which states that the enthalpy of formation is negative.

negative enthalpy of formation indicates that the heat is released during the reaction process. the heat is released from reaction to the surroundings the enthalpy is expressed with a negative sign with the energy given out in the reaction process.

the formation of water takes place by giving out heat which is -285.8 kj/mol.