Complex sentence: More in-depth investigations were conducted by Esther Levenson, Pessia Tsamir, and Dina Tirosh, who interviewed a pair of sixth-grade students who were performing highly in their mathematics class.
Split into simpler sentences: More in-depth investigations were conducted by Esther Levenson, Pessia Tsamir, and Dina Tirosh. The researchers interviewed a pair of sixth-grade students who were performing highly in their mathematics class.