Given the age of the meteorite is 4.5 billion years old with 78 atoms of lead-206 the answer should be B. 156. The half-life of uranium-238 in order to decay into lead-206 is 4.46 billion years, which means that the original number of atoms is 156.
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.
Most heterotrophs are chemoorganoheterotrophs<span> (or simply </span>organotrophs<span>) who utilize organic compounds both as a carbon source and an energy source. The term "heterotroph" very often refers to chemoorganoheterotrophs. Heterotrophs function as consumers in </span>food chains: they obtain organic carbon by eating autotrophs or other heterotrophs. <span>Most </span>opisthokonts<span> and </span>prokaryotes<span> are heterotrophic</span>
