Answer:
b concentration insid e and out side the cell
What is different with retroviruses in reproduction is that they do not kill their hosts at first because they can still insert their own genome. This process is what is known the reverse transcription. This is done by different proteins.
If they are trying to convert any measurements or just measure out the chemicals, it wouldn't be very familiar to them so they could make a mistake that can result of too much or too little of the chemicals, which can make the chemicals react differently.
Since due to having the coronavirus, the immune system is already tired of fighting off such a tough disease. Since it's so weak, one small bacteria can make your body react to it in ways you wouldn't think it may, because the immune system isn't working much.