If you are referring to later seasons, the 10th episodes follow different arcs:

: Index provides thematic commentary by comparing the scientific pursuit of "SYSTEM" (Level 6) to the magical concept of the Tree of Sephiroth from Kabbalah. Episode 10 in Other Seasons

: Genetic copies of Mikoto created for the Level 6 experiment.

To Aru Majutsu No Index Episode 10 Site

If you are referring to later seasons, the 10th episodes follow different arcs:

: Index provides thematic commentary by comparing the scientific pursuit of "SYSTEM" (Level 6) to the magical concept of the Tree of Sephiroth from Kabbalah. Episode 10 in Other Seasons

: Genetic copies of Mikoto created for the Level 6 experiment.