Resolving the Structure and Kinematics of the Youngest HII Regions and
  Radio Jets from Young Stellar Objects
  In this contribution we explore the new science that a Next Generation Very
Large Array (ngVLA) would be able to perform on the topics of the youngest HII
regions and (proto)stellar jets. Free-free continuum and radio recombination
line (RRL) emission are often the only way of peering into the dense envelopes
surrounding (proto)stars of all masses, and trace their initial feedback in the
form of `radio jets', `hypercompact HII regions', or photoevaporating,
partially-ionized flows. Properly disentangling free-free from dust emission is
also mandatory in studies of protoplanetary and accretion disks. Current VLA
research has reached an impasse in which a population of faint ionized radio
sources, probably corresponding to the above mentioned objects, is detected,
but their nature is mostly unknown. The ngVLA would allow us to resolve the
density structure and kinematics of such sources, revolutionizing our knowledge
of star formation across the entire stellar-mass spectrum.
