Answer:
Diseases can be spread though all
Step-by-step explanation:
airbone, coughing sneezing and all that.
skin to skin contact, maybe through cuts or door handles that has been infected and bla bla.
blood, mother to child diseases, infected blood and so on.
then moisture could be the answer cause the other ones I'm sure of, but this is water vapour, droplets of water within a solid or also in the air. it can be infected cause we know you can have infected water or something and also transmitted through the air...so can also be under airbone.