Cyanobacteria, also known as blue-green algae, are found in vast quantities in fresh and salt water. Cyanobacteria are able to conduct photosynthesis. By utilising energy from the sun, they produce carbohydrates from water and carbon dioxide. As a byproduct, they produce oxygen. So cyanobacteria provided oxygen to the atmosphere that allowed other lifeforms to develop.
The correct answer would be D, gravity. As moving water will cause rocks to erode as well as wind, and animal habitation.
C. The process by which green plants and some other organisms use sunlight to synthesis food from carbon dioxide and water.
i think the answer is B :)
C. Hardness is the answer
