Answer:
α-amino group
Explanation:
The α-amino group on the hemoglobin binds with the CO2 and this action causes a conformational change in the structure of hemoglobin that ultimately causes the release of linked oxygen. When CO2 is binded to the hemoglobin the whole complex is termed as carbamino-hemoglobin.
The Precambrian time refers to the time 4.5 billion to 542 millions year ago. This period is characterized by having reduced atmosphere and included reduced compounds. Scientists believed that atmosphere at that time was devoid of free oxygen and CO2 was present in excess. Before the complex life evolved on the Earth, the Precambrian Earth's ocean contained dissolved carbon dioxide.