Why don't plants require a digestive system like humans?

No! They directly make in their bodies the simpler molecules that are directly put into use by the body. Because there is no requirement of breaking complex food into simpler substances, plants don't need a digestive system. In other words, let's say humans eat rice, which is essentially starch. read more

The carbs, proteins, fats, minerals, etc need to be in their simple forms to be utilized. read more

Plants, on the other hand, generate their own energy. They use water and various nutrients from the soul along with chlorophyll and sunlight in order to grow. The combination of these factors in a chemical reaction creates the energy that they need. Therefore, they don't have a digestive system like that which you are referring to. read more