Understanding the dynamics of partons in general, and non perturbative sea, in particular, will be crucial for the understanding of strong interactions. Correlations of the spin of the target or/and the momentum and the spin of quarks, combined with final state interactions define the azimuthal distributions of produced particles. Production of correlated hadron pairs, in addition, will play an increasingly important role in the interpretation of pion electroproduction data.
Studies of the nucleon structure beyond the traditional leading twist and current fragmentation, provide qualitatively new tools to study the nucleon structure and extension of large $x$ region well covered by JLab, to large $Q^2$ at EIC will be very important in interpretation of the data from JLab.
The large acceptance of the EIC combined with clear separation of target and current fragmentation regions will also provide a unique possibility to study the nucleon structure in the target fragmentation region and correlations of target and current fragmentation regions.