Complex sentence: In aerobic organisms the energy needed to fuel biological functions is produced in the mitochondria via the electron transport chain, in addition to energy reactive oxygen species (ROS) are produced which have the potential to cause cellular damage.
Split into simpler sentences: In aerobic organisms the energy needed to fuel biological functions is produced in the mitochondria via the electron transport chain. In addition to energy, reactive oxygen species (ROS) are produced which have the potential to cause cellular damage.