Biotics is the ability for some lifeforms to sense, create and manipulate mass effect fields. This process uses Element Zero nodules embedded in body tissues. Bio-Amps are required by most species to use their abilities effectively, though all species generally use them when maximum performance is needed for work, sport or combat.
The ability to sense mass effect fields makes biotics sensitive to synthetically generated fields, and exceptionally powerful ones are described to feel like nails on a chalkboard.
Most specialize in perfecting a few types of fields that are relevant for their purposes, due to the immense training that some require. Individual techniques, schools of thoughts and purposes make it difficult to formalize them into one-word abilities.
High Mass Fields
A barrier is an ability where in the biotic constructs a high-gravity field around themselves. Unlike kinetic barriers installed in combat hardsuits, the barrier is a constant field that can also protect against blunt force.
The most common barrier a biotic is able to make is at personal range, which can be used in place of kinetic barriers if caught unequipped. With enough practice, a biotic can extend it outward enough so that it does not interfere with the kinetic barrier systems.
Extending the barrier to deny entry or cover a group of people is a more advanced skill. It requires a keen perception and control of mass effect fields to keep it balanced. While this high barrier of entry does not grant the asari exclusivity, it is most commonly practiced by them. A small number of highly talented biotics can also move the field while it's active in order to escort a group through a hostile zone.
While the fields can hold up against an explosion or fire, it is not precise enough to keep an atmosphere in against the vacuum of space long enough to be useful. Only a synthetic field can do that.