there are already many japanese plants, so not the iris. I don't see any water features here and I have no idea what a fence will do. Also I don't see a reason for a spirit gate, so the answer should be a water feature.
Viruses can be described as non cellular, microscopic, infective agent that are composed of genetic material ( DNA or RNA), which is surrounded by a protenaceous coat known as viral capsid.
It means that there can be RNA ( ribonucleic acid) and DNA ( deoxyribonucleic acid) based viruses.