Ancient cyanobacteria released which assisted in creating the atmosphere as we know it today.
a. lead
b. ore
c. hydrogen
d. oxygen

The ancient cyanobacteria releases oxygen which assisted in creating the atmosphere as we know it today.  This bacteria can perform photosynthesis and are similar to the plants or trees. Their photosynthesis produces oxygen changed the atmosphere made it oxidizing. Cyanobacteria is also called as Cynophytha. 

Endurance would be my answer

Answer liquidity;