The energy profile diagram for a three step reaction in which first step is slowest and last step is fastest. (Assume that reaction is exothermic)

According to Arrehenious equations,
$\mathrm{k}={\mathrm{Ae}}^{-\mathrm{Ea}/\mathrm{RT}}$ greater is Ea, the smaller is K, i.e. ,rate of reaction $\propto \frac{1}{ \mathrm{height} \mathrm{of} \mathrm{energy} \mathrm{barrier} }$, steps leading to the height of peak will not be R.D.S. (rate determining step) if the concentration used in some other step is sufficiently high. Since first step is R.D.S. Therefore first peak should be high as it is in (3).