Answer:
MIXTURE
Explanation:
A mixture is a substance composed of a combination of other different substances. These component(s) of a mixture are physically combined, meaning that there is no chemical linkage between the individual components/constituents of a mixture.
This is the case of the gravel described in this question. The components of gravel can be separated using physical means because they are not chemically bonded to one another, hence, no chemical reactions are needed to separate different parts of gravel into pure substances. This makes gravel a MIXTURE.
Since chromium has 24 as its atomic number (which mean that it has 24 proton and 24 electron in neutral ground state), the electron configuration for the chromium would be :
1s^2 , 2s^2 , 2p^6 , 3s^2, 3p^6 , 3d^5 , 4s^1
Answer: I. The number of molecules is conserved.
III. Atoms are neither created nor destroyed
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.
For example: 
Thus in the reactants, there are 4 atoms of hydrogen , 2 atoms of oxygen and 2 atoms of sodium.Thus there will be 4 atoms of hydrogen, 2 atoms of oxygen and 2 atoms of sodium in the product as well.
Simply put, MA = Force Out / Force in. That's the way it is usually stated. The force out is normally what you need to move. The force in is what you need to supply to get the force out. Most machines will give you an MA of more than 1. Some (like your arm) will give you less than 1 and others (like this one) will give you exactly one.
This one is frictionless, otherwise it would slip into less than one if it had friction.
Answer B
Explanation:
check the steps in the attached image
