Topsoil because plants and decaying animals add more humus to the soil
<span>Define symbiosis, commensalism, mutualism, and parasitism. 2. Give two examples of pairs of organisms that have thesesymbiotic relationships: commensalism, mutualism, and parasitism </span>
To Find :
How many moles are in 
atoms of iron.
Given :
We know, 1 mole of any element or compound contains exactly 
( Avogadro's Number ) atoms/compound .
Now, 
So, number of moles in given number of atoms are :
Hence, this is the required solution.
Answer: 2.23 is the difference.
Explanation: Sodium has an electronegativity of 0.93 and Chlorine has an electronegativity of 3.16, so when Sodium and Chlorine form an ionic bond, in which the chlorine takes an electron away from sodium, forming the sodium cation, Na+, and the chloride anion, Cl-.
