Which organism obtains its energy from dead or decaying matter?

saprotrophs or saprophyte

A saprophyte or saprotroph is an organism which gets its energy from dead and decaying organic matter. This may be decaying pieces of plants or animals. They are consumers in the food chain.Bacteria and fungi are important saprotrophs.

Saprophyte is the organism obtains its energy from dead or decaying matter

Explanation: Saprophytes don't have chlorophyll and therefore, cannot prepare their food. They obtain nutrients from dead and decaying matter. Digestive juices secrete by the saprophyte on dead and decaying matter and convert it into a solution. They then absorb the nutrients from it. These enzymes convert organic food substance into a simple one.

your answer is "the 1950's"

thinking it would be d not too sure but i think it's right