Question

which was not a source of water for earths oceans? volcanic outgassing asteroids cyanobacteria meteorites

Explanation:

Volcanic outgassing released water vapor which condensed to form water. Asteroids and meteorites (especially carbonaceous chondrites) are believed to have delivered water to Earth. Cyanobacteria are photosynthetic bacteria that produce oxygen (through photosynthesis) but not a source of water for the oceans.

Answer:

cyanobacteria