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.
Aminos acids are used to build proteins
The term for the type of key that biologists used in separating<span> groups of organisms that are based on couplets is called taxonomic key. This key is very useful in the identification and classification of a </span>specific organism and it usually has an analytical characteristic.<span> </span>
