Answer:
Oxygen for respiration and Carbon dioxide for photosynthesis
Explanation:
A single piece of coiled DNA is called a plasmid.
Answer:
Mitochondria
Explanation:
This was the first endosymbiotic event during our primitive cell basically engulfed an aerobic bacteria which later formed into mitochondria. This is why mitochondria has its own DNA as well (called the mitochondrial DNA)
