Answer :There was enough oxygen in the atmosphere to support a major burst of life on Earth
Explanation:
The Great Oxygen Event marks the time, approximately 2.5 billion years ago, when there was enough oxygen in the atmosphere to support a major burst of life on Earth
For the first half of the Earht's history, there was no oxygen in the atmosphere. It was inhabited only by single-celled organisms.Of those simple life forms, the cyanobacteria may have. evolved a way to take energy from sunlight, and used it to make sugars out of water and carbon dioxide. They used the same chemical process we know as photosynthesis. This released vast quantities of oxygen into the atmosphere and triggered the evolution of complex life.
Distribute blood through the body
Answer:
For example, delays in mitosis are often ascribed to 'activation' of the mitotic checkpoint, a descriptor that fails to recognize that the checkpoint by definition is active as the cell starts mitosis. Conversely, the completion of mitosis in the presence of misaligned chromosomes is often automatically interpreted to indicate a defective checkpoint, even though in the absence of critical testing alternative interpretations are equally likely. In this article, we define the critical characteristics of checkpoints and illustrate how confusion generated by the inconsistent use of terminology may impede progress by fostering claims that mean very different things to different researchers. We will illustrate our points with examples from the checkpoint that controls progression through mitosis
Explanation:
The contamint would evaporate
