What led to oxygen becoming a major part of earth's atmosphere

Explain why the plants cortex would serve as the best food source for animals

Explain the significance of the increased cell specialization of the volvocine line

The picture showed normal blood cells which are around and sickle cells which appear much longer people with sickle-cell suffer from the sickle cell anemia which is inherited diseaseit is caused by a change in gene responsible for production of hemo goblin this type of change is known as an