The scientist observes at what rate is the concentration increasing or decreasing.
The answer is: [D]: a reactant.
________________________
Answer:
The volume of a given amount of gas is inversely proportional to its pressure when temperature is held constant (Boyle's law). Under the same conditions of temperature and pressure, equal volumes of all gases contain the same number of molecules
Explanation:
Fossil C is the youngest. Layers further down were placed earlier than others. Because C is on the top layer, it must be the youngest (unless a disaster mixed up all the layers!).
