Answer: (1) Putrefaction
(2) Biodegradable
(3) Refuse.
Putrefaction refers to decomposition of organic substances usually dead plants' and animals' bodies by microorganisms.
Therefore, it matches with first definition that states the decay of organic matter caused by microorganisms.
Biodegradable substances are decomposed by living organisms such as microorganisms.
Therefore, it matches with the second definition that states susceptible to decomposition by living organisms.
Refuse refers to something which is no longer useful.
Therefore, it matches with the third definition of waste.