It is symbiosis, but also called a commensalism relationship because the remora is getting its food and the shark has no benefit.
One method I know of is comparing a sample of the rock to other samples which the scientist already knows the age of. I forgot what this method is called but I know it's used by lazy scientists that use other scientist findings like the age of a rock to compare to their own work
Because most waste produced in the cell is toxic when it accumulates.
Hope this helps!
Explanation:
To calculate the pH of an aqueous solution you need to know the concentration of the hydronium ion in moles per liter (molarity). The pH is then calculated using the expression: pH = - log [H3O+].