State the resemblance and difference between $\sigma$ ($\sigma$) and $\pi$ ($\pi$) bonds.

(N/A) Resemblance: Both $\sigma$ and $\pi$ bonds are covalent bonds formed by the overlapping of atomic orbitals. Both involve the sharing of electron pairs between two atoms.
Differences:
$1$. $\sigma$ bond is formed by the head-on (axial) overlapping of atomic orbitals, whereas $\pi$ bond is formed by the lateral (sideways) overlapping of atomic orbitals.
$2$. $\sigma$ bond allows free rotation of atoms around the bond axis, while $\pi$ bond restricts rotation.
$3$. $\sigma$ bond is stronger due to greater extent of overlapping, whereas $\pi$ bond is weaker due to lesser extent of overlapping.
$4$. $\sigma$ bond can exist independently, whereas $\pi$ bond is always formed in addition to a $\sigma$ bond.