Which geologic term or phrase explains why the bottom stratum in a section of rocks is the oldest

The diagin dilutepage 6 of 12a6a5(a)fluorine, chlorine, bromine and iodine are placed in the same group of theperiodic table.state the common name used to describe elements in this group.(i)state the group in which the elements are placed and explain whythey are placed in that group.(ii)which of the above named elements is a solid at roomtemperature and pressure?

What is dhmo? hint: you find it everywhere something is wet..

The compound formed from 2 atoms of hydrogen and one atom of oxygen is