O plural de oxygen é:

Leia o texto abaixo para responder a questão.

A rare plant has reappeared after more than a century in hiding.

The pinkish-flowered plant, known as grass-poly, was found growing on the banks of an old farmland pond in Norfolk.

The mystery species "came back from the dead" after seeds submerged in the mud were disturbed during work to restore the pond.

The seeds of the plant remained buried in the mud, like a "time capsule". When willows were pulled out to restore the pond, this disturbed the soil and let in light, allowing the seeds to germinate.

 "There's no oxygen, it's very dark, and it's perfect for preserving seeds," says Prof Sayer, who is part of UCL's Pond Restoration Research Group. The discovery shows plants believed extinct can be brought "back to life" with good conservation, he added.

Fonte: adaptado de https://www.bbc.com/news/science-environment-55104153