Wheat: 

Wheat is a grass widely cultivated for its seed, a cereal grain which is a worldwide staple food. The many species of wheat together make up the genus Triticum; the most widely grown is common wheat.

Flour:

Flour is a powder made by grinding raw grains, roots, beans, nuts, or seeds. It is used to make many different foods. Cereal flour is the main ingredient of bread, which is a staple food for most cultures.

Density: The bulk density (g/cm3) of flour is the density measured without the influence of any compression. The bulk densities of flours ranged from 0.762 g/cc to 0.820 g/cc.