The Archean atmosphere is thought to have nearly lacked free oxygen.
They were able to thrive on the early, warmer Earth with an atmosphere that lacked oxygen.
This means that the ocean depths were lacking oxygen, so no higher forms of life could survive.
The latter had a dense moist atmosphere; but one which lacked oxygen.
However wood placed underwater lacks sufficient oxygen, and colonization cannot occur.
"But if there's too much standing water, they'll lack oxygen and die."
Poor nourishment by the placenta, which means the baby lacks oxygen and doesn't survive.
If there is a bluish cast over the entire body, the blood may be lacking sufficient oxygen.
This is determined by how long the brain lacked oxygen, and whether nutrition to the brain was also affected.
Suddenly, the room was not only too hot; it also seemed to lack sufficient oxygen for Tom's needs.