lichens, corals, viruses, corals, viruses and carnivourous plants are difficult to classify :)
It is because viruses are not made up of cells
Do you mean fluorine? Fluorine is difficult to deal with as it is highly poisonous.
Because you are an idiot
Describe a situation where you have had to deal with a difficult customer what did you do what was the outcome
Viruses are so difficult to combat because they are very good at assuming control of cells and multiplying themselves to spread and produce toxins.
fire him
how to deal with a difficult customer in a retail store
The viruses are not living in simple condition,but when they get host cell or host organism they come in alive form and be active & reproduce.The viruses contain strong coated wall around them made of proteins called "Capsid"which is very difficult to destroy.This Capsid contains special materials which penetrates the host cell's wall and make RNA or DNA(genetic material) of viruses entered in host cell.Different types of viruses contains different type of Capsids and it is very difficult to deal with them.Note:- Some bacterium contain "Restriction enzymes" which stops duplication of viral genes and thus make viruses ineffective to them.
General frustration is difficult to deal with when everything seems to be going wrong.
Viruses use their host's metabolic enzymes and some viruses mutate very quickly so they can easily become resistant to drugs. Viruses are almost biologically inert until they infect a cell.
It is difficult because viruses lack the ability to replicate themselves and theey lacks energy metabolism and other pathways that living things have. Viruses are totally depending on their host. If they want to replicate, they have to infect the host.