“And of everything We have created pairs.” [Al-Qur’an 51:49]
This refers to things other than humans, animals, plants and fruits. It may also be referring to a phenomenon like electricity in which the atoms consist of negatively – and positively – charged electrons and protons.
“Glory to Allah, Who created in pairs all things that the earth produces, as well as their own (human) kind and (other) things of which they have no knowledge.” [Al-Qur’an 36:36]
The Qur’an here says that everything is created in pairs, including things that the humans do not know at present and may discover later.