Answer
a balance and a graduated cylinder
Explanation
Density is mass per unit and it is property characteristic of a substance. The arrangement of the mass of atoms and their size is what determines the the density of a substance.
For a student to measure the density of seawater he/she is required to use a balance and a graduated cylinder where a balance will be used to measure the mass of the mineral sample and then a graduated cylinder to determine the volume.
Well those that are in that ecostems could died from no water or the could walk on it and it breaks
Enzymes <em><u>act as catalysts in Chemical reaction of cells. </u></em>And they <u><em>can lower the required activiation energy for reaction in living organisms. </em></u>