2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/200073Giving three examples, the form factors of the nucleon, the polarisability of the charged pion and the interference of the $S_{11}(1535)$ with the $D_{13}(1520)$ excitation of the nucleon in the $ηp$-decay channel, it is argued that the hadron structure at low momentum transfer is highly significant for studying QCD.7 pages, 9 figures. Contribution to the International School of Nuclear Physics, 29th Ccourse, "Quarks in Hadrons and Nuclei", Erice, Sicily, 16 - 24 September 2007High Energy Physics - Phenomenologytext