Although the numbers and virulence of microorganisms determine whether a person acquires an infection, another major factor is:

The environment and the human's body contain microorganisms.

Explanation:

Most of them are not disease causing organisms. It is only when there is infection that it is now a matter of how the host can defend that determines how fast the person recovers.

The use of antimicrobial drugs can lead to serious infections that is caused by drug resistant microorganisms.

yes many times

explanation:

answer; 4% i believe this is correct;