One group of reptiles, characterized by the fossil Archaeopteryx, led to the evolution of birds. The correct answer is birds
Answer: Erythrocytes also known as Red blood cell compose about 40-45% of blood
Explanation: 40-45% of the blood volume is erythrocytes i.e the red blood cell. It contains heamoglobin a special protein that carries oxygen to the lungs.
The balanced equation will be 2HgO--->2Hg+O2
2hrs is the answer I guess so.