definition
An ionized gas consisting of positive ions and free electrons in proportions resulting in more or less no overall electric charge, typically at low pressures
sentence
This expansion of the atmosphere significantly increases the number of microscopic collisions between the satellite and the gases and plasma of the upper atmosphere.
The photons can break apart, or ionize, molecules and atoms of the atmosphere into protons and electrons, producing plasma.
difficulty
hard
toefl frequency
2
toefl classification