Final answer:
Inputting energy into a living system decreases entropy, as it helps build complex structures and drive endergonic reactions, reducing the disorder within the organism. The correct option is a).
Step-by-step explanation:
The question asks which best describes the effect of inputting energy into a living system. The answer is that it decreases entropy within the system. Entropy is a measure of disorder, and higher levels of entropy correspond to higher states of disorder.
By inputting energy, for instance in the form of sunlight for photosynthesis in plants, the system can build complex structures from simpler ones, thus decreasing the entropy or disorder.
This is because living systems are open systems that can decrease their entropy as a result of energy input, often to drive endergonic reactions, which are reactions that require energy to proceed.
Processes like photosynthesis and cellular respiration are good examples of how the input of energy decreases the local entropy within a living organism. Option a) is the correct one.