A positively charged ion is called cation.
A negatively charged ion is called anion.
A salt is formed by the ionic bonding of a cation and an anion.
pH is a measure of the hydrogen ion concentration in a solution.
The system of classification relates to the diversity of species because the system of classification is how we organize the diversity of species. With out it we would have a hard time trying to determine which animals belong with which group. There would be no order, just chaos of trying to determine animal likeness of one another.
To cut this answer short, it helps them organize organisms.
Day and night is caused by the earth rotating on its axis throughout 24hrs
Volcanoes influence our lives by shaping the land around us as they form, making the soil fertile and creating havoc when they erupt.