Final answer:
The early conditions of Earth were different than today, with no oxygen in the atmosphere. The first organisms to develop were anaerobic organisms that could survive without oxygen. Over time, phototrophic organisms evolved and produced oxygen as a by-product of photosynthesis. The correct option is b. Microorganisms; They can survive in harsh conditions
Step-by-step explanation:
The early conditions of Earth were different than the conditions today, particularly with regard to the atmosphere. The atmosphere during the first 2 billion years of Earth's existence was anoxic, meaning there was no oxygen. Therefore, the first organisms to develop were anaerobic organisms - organisms that can grow without oxygen.
These first organisms likely flourished in protected environments such as ocean depths or beneath the Earth's surface, as the early Earth was subjected to strong radiation and volcanic activity. These harsh conditions may have led to the evolution of prokaryotes - the first forms of life on Earth that could withstand these conditions.
It wasn't until phototrophic organisms, which convert solar energy into chemical energy, appeared within one billion years of Earth's formation that oxygen began to be produced as a by-product of photosynthesis. From these organisms, cyanobacteria evolved and played a crucial role in oxygenating the atmosphere. The correct option is b. Microorganisms; They can survive in harsh conditions