Given a scientific question, generate a correct answer to it.

Ex Input:
What is the study of the energy transformations that occur in a collection of matter?

Ex Output:
thermodynamics

Ex Input:
The process of breaking down food into nutrients is known as __________

Ex Output:
digestion

Ex Input:
Net production efficiency allows ecologists to quantify how efficiently organisms of a particular what incorporate the energy they receive into biomass?

Ex Output:
trophic level