The correct answer is - cyanobacteria.
The atmospheric oxygen came from the cyanobacteria. These were one of the earliest living organisms on Earth. The cyanobacteria was using photosynthesis in order to create its own food. The photosynthesis process requires sunlight, carbon dioxide, water, and oxygen. The oxygen is mostly released as a waste product from the process of photosynthesis, thus the cyanobacteria were literally releasing oxygen that was ending up into the atmosphere. As more and more cyanobacteria there were across the planet, more and more oxygen they were releasing into the atmosphere, slowly changing the composition of the atmosphere, and setting the basis of it as we know it now.
E. indoor plumbing
because this comes in agriculture wich hellped southeast development
Climate change has multiple effects on people and animals.
Every American is vulnerable to climate change impacts on their health at some point in their lives.
Climate change can have a range of impacts on physical, mental, and community health.
A warmer climate is expected to increase the risk of illnesses and death from extreme heat and poor air quality.
Climate change will likely increase the frequency and strength of extreme events (such as floods, droughts, and storms) that threaten human health and safety.
Climate changes may expose more people to diseases.
Some groups of people (e.g., the very young and the very old) are especially vulnerable to health impacts.
-- so that other scientists can reproduce your experiment in their labs
-- so that when you go back and read your own experiment next year,
you'll be able to remember and understand what you did
