Which phenomenon best supports the theory that matter has a wave nature?

Explain the method of the Davisson and Germer experiment and its results.

In the Davisson-Germer experiment,an electron beam of energy $75 \ eV$ falls normally on the surface of a crystal. If the maximum intensity is obtained at an angle of $45^o$ to the direction of the incident beam,then the inter-atomic distance in the lattice plane of the crystal will be .............. $\mathring{A}$

Explain Heisenberg's uncertainty principle.

Statement $1$: The Davisson-Germer experiment established the wave nature of electrons. Statement $2$: If electrons possess wave nature,they can undergo interference and diffraction.

In the Davisson-Germer experiment,an electron beam with a wavelength of $1.5 \ \mathring{A}$ is incident normally on a crystal with an atomic spacing of $3 \ \mathring{A}$. At what angle (in degrees) will the first maximum be formed?