A hypoxic or anoxic zone

Yes plants can live in anoxic soil. an example of a plant that can live in anoxic soil is the mangrove. A mangrove can live in anoxic soil because of little arial roots called pnuematophores that are not submerged by water during the day, this allows them to draw oxygen into the underground root system.

Toxic.

yes, anoxic photosynthesis

Soil that contains oxygen is known as oxic soil. On other hand soil which lacks the oxygen is known as anoxic soil