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.
Compact sponge is the answer :3
Physical Change, although the answer is widely disputed.
That organ is called the rectum, or more coomonly, the anus. The rectum is the final part of the large intestine and the digestive system, where food that has had all its nutrients extracted (as much as possible, anyway) is sent to be compacted and sent out through the anus in the form of excreta. The contents in the rectum is mostly indigestible fiber and other materials. The rectum at its end connects to the bodily orifice known as the anus.