They are considered so because are the indispensable parts of the nature cycle.Without formation,decay cannot be possible and similarly,formation cannot be possible without decay.In addition to this,THEY ARE IN A CHRONOLOGICAL MANNER SET BY NATURE and that's why cannot be seperated and so together constitute the cycle of nature.
It is not c or d. I think it is a.
Enhancers are eukaryotic DNA sequences that can be used to elevate transcription and have variable positions and orientations.
Answer: She should Avoid Contact with other people's bodily fluids.
Explanation: Hope that helps! (: