Microorganisms that are capable of causing disease are called pathogens. Although microorganisms that cause disease often receive the most attention, it is important to note that most microorganisms do not cause disease. In fact, many probably provide some protection against harmful microorganisms because they effectively compete with the harmful organisms for resources, preventing them from growing.
It is an example of a withdrawal reflex.
Answer:
I think it is the last one
It is to replace old, worn out cells.
One single cell divides to two, etc. etc.
