Answer:
The correct answer will be option E.
Explanation:
The features given in the question are the characteristics features of the group of bacteria belonging to Cyanobacteria.
These Cyanobacteria are the prokaryotes which are capable of synthesizing the food through a process called photosynthesis. These bacteria use sunlight as their energy, use water and air to synthesize food. They under anaerobic condition synthesize the nitrogen in special structures called heterocyst, a characteristic feature of cyanobacteria.
Thus, the features given in the question are:
1. contain photosystems to carry out photosynthesis.
2. producing oxygen
4. contain phycobilins
6. Hetrocysts: nitrogen-fixing structures.
7. The ancestor of plant chloroplasts.
Thus, option E is the correct answer.