(a) Oxygenic with nitrogenase(b) Oxygenic without nitrogenase(c) Non-oxygenic with nitrognase(d) Non-oxygenic without nitrogenase[CBSE AIPMT 2001]
Correct Option (a) Reason : Cyanobacteria (Gk. Kyanos = dark blue; bakterion = a staff) also known as blue-green algae.
It is a very important group of photosynthetic bacteria in the history of life on earth.
The cyanobacteria fix atmospheric nitrogen through the help of enzyme nitrogenase and also show oxygenic photosynthetic.