[en] Some characteristics of Extensive Air Showers in the energy region of the knee of the cosmic ray spectrum (E₀ = 10¹⁵ - 10¹⁶ eV) are discussed, to discriminate its possible 'hadronic' from 'astrophysical' origin. Within the accuracy of such data, no clear 'anomaly' suggesting a non expected behaviour of hadronic collisions at such energies is observed. Some approaches to the study of hadronic interactions, as observable through EAS experiments, are discussed. Such data can be significant to test the high energy interaction models used for composition analysis