Cyanobacteria can cluster together into colonies called , with some discovered in Western Australia that are 3.5 billion years old. Cyanobacteria produce oxygen and convert sunlight to energy using . Plants and arthropods didn't make the transition to land until near the end of the Period. Diverse multicellular eukaryotes didn't appear until the period. A large multicellular eukaryote requires more to survive than a single-cell eukaryote. Respond to the following based on your reading. Describe the biological chemical processes that were responsible for producing oxygen in Earth's atmosphere, eventually leading to the Cambrian Explosion. Explain the importance of oxygen in the evolution of large multicellular animal life.