a better statement would be that "every experiment ever done has confirmed the hypothesis that energy is conserved"
An example where space would be a limiting factor would be this: Wolves live in a very good habitat for them - there are plenty of animals to be found and eaten. However, because their current habitat is rather limited, they cannot expand beyond a certain size because otherwise they would interfere with the habitat of each other and also reduce the amount of necessary food in the environment.
They cannot reproduce outside of a living cell
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.
