Which of the following does $NOT$ have a triclinic structure?

The total number of Bravais lattice arrangements in different crystal systems is

The three-dimensional graph of lattice points which sets the pattern for the whole lattice is called:

The crystal system with edge lengths $a \neq b \neq c$ and axial angles $\alpha = \beta = \gamma = 90^{\circ}$ is '$x$' and the number of Bravais lattices for it is '$y$'. $x$ and $y$ are:

Explain the concept of a two-dimensional lattice and a hypothetical two-dimensional crystal.

State the characteristics of a crystal lattice.