Answer: Through diffusion
Explanation:
Oxygen can be defined as the most abundant element on earth. It is a gas at room temperature. It becomes the part of the earth crust by the process of diffusion.
Diffusion is a process of movement of molecules from a region of high concentration to the low concentration. The oxygen remains in high concentration in the atmosphere diffuses into earth crust at low concentration.
Answer: 4
Explanation: Your counting 4 for each interval. 9+4 =13 13+4 =17 17+4 =21 and so on.
Milk mixture and heterogeneous
Answer:
CO2
cardon dioxide is produced
Answer: The atom count for each element on the reactant side of a balanced chemical equation is equal to the atom count for each element on the product side of the same equation
Explanation:
According to the law of conservation of mass, mass can neither be created nor be destroyed. Thus the mass of products formed must be equal to the mass of reactants taken.
In order to get the same mass on both sides, the atoms of each element must be balanced on both sides of the chemical equation.

Thus there are 4 atoms of hydrogen on reactant as well as product side.
Also there are 2 atoms of oxygen on reactant as well as product side.