\[\left( c \cdot c^{2} \right)^{2} \cdot \left( c \cdot c^{2} \right)^{3} =\]
\[= c^{2} \cdot c^{4} \cdot c^{2} \cdot c^{6} =\]
\[= c^{2 + 4 + 2 + 6} = c^{15}.\]