I think its D. formal-operational
A hydrometer or areometer is a <span> instrument that always </span><span>measures the specific gravity relative density of liquids and the ratio of density of the liquid to the density of liquid to water.
Hope This Helps Have A Great Day :)))))</span>
Producers are the plants of the food chain. They use the sun or other inorganic energy sources as a way to make food for themselves.
