Answer:
Respiration...................
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.
Answer: The virus weakens as time passes.
Explanation: The virus will weaken continuously during transmission, and will reduce its toxicity after several generations of transmission, without causing much harm to the human body.
The magnification power level of the microscope
