<h2>Answer:</h2>
Option A is correct
Adding an enzyme to decrease the activation energy of the reaction
<h2>Explanation:</h2>
Enzymes are the biological catalyst. They are proteins in nature. They are naturally found in humans,animals,micro-organisms,plants etc. They catalyze the chemical reactions by lowering activation energy and without being consumed in it.
 
        
        
        
<span>Cations mix with anions, so you know NH4+ won't mix with K+ and SO4(2-) won't miix with F-. For the reason that NH4+ and F- together have single charges, they'll mix in a 1:1 ratio, NH4F. There's two charges on SO4(2-), so it'll need two K+ to mix with, K2SO4.</span>
        
                    
             
        
        
        
Molecule, a group of two or more atoms that form the smallest identifiable unit into which a pure substance can be divided and still retain the composition and chemical properties of that substance. 
While Atoms are single neutral particles, 
Molecules are neutral particles made of two or more atoms bonded together.
Exaplmes for molecules
H2O (water)
N2 (nitrogen)
O3 (ozone)
CaO (calcium oxide)
C6H12O6 (glucose, a type of sugar)
NaCl (table salt
And examples for atoms
Neon (Ne)
Hydrogen (H)
Argon (Ar)
Iron (Fe)
Calcium (Ca)
Deuterium, an isotope of hydrogen that has one proton and one neutron.
Plutonium (Pu)
F-, a fluorine anion. 
 
        
             
        
        
        
Answer:
water is H2O having different structure than alcohol R-OH which means they have different properties too.
Explanation:
In water one oxygen atom  is covalently bound with  two hydrogen atoms while alcohol is an organic compound  having Oh group attached to the carbon chain. 
Other than liquid water can occur in solid form that is ice and in gaseous form that is vapors too while alcohol only present in liquid form.
heat of evaporation of alcohol is lower than water means water need more heat to evaporate than alcohol that is why we can say alcohol having more cooling effect than water. 
 
        
             
        
        
        
Answer:
Detail is given below
Explanation:
Atomic radii trend along group:
As we move down the group atomic radii increased with increase of atomic number. The addition of electron in next level cause the atomic radii to increased. The hold of nucleus on valance shell become weaker because of shielding of electrons thus size of atom increased.
As the size of atom increases the ionization energy from top to bottom also  decreases because it becomes easier to remove the electron because of less nuclear attraction and as more electrons are added the outer electrons becomes more shielded and away from nucleus.
In A we can see that there is one positive charge and force of attraction is 2.30×10⁻⁸ N and distance is 0.10 nm
In B we can see that negative charge is further away from nucleus because of greater distance thus force of attraction will be less. 0.58×10⁻⁸ N
In C this distance further increases and force also goes in decreasing 0.26×10⁻⁸ N.