The energy used to obtain, transfer, and transport materials within a organism comes directly from ?

Mitochondrion a singular word for mitochondria is a "powerhouse" organelle of the cell. 

Mitochondrion is an important organelle in most living organisms because it is where biochemical processes of living organisms such as respiration takes place. The mitochondrion has a smooth outer membrane but a larger inner membrane. The inner membrane is about 70% protein and is very convoluted because that can even fit inside the outer membrane. Mitochondrion is the carrier of the Kreb's cycle in the matrix and it is responsible for the transfer of electron chain found in the cristae of the inner membrane.

When you are making a guess you are forming a hypothesis