In the latter case the resistance is caused by dissipation of mechanical energy when the configuration or the direction of flow is sharply changed, by the formation of vortices and secondary flows as a result of the flow breaking away, by the centrifugal forces, etc.
Animals depend on plants for food as plants produce food and energy which animals can't, so, herbivores eat plants to get energy, carnivores eat herbivores and other carnivores for energy and omnivores eat all four, plants, herbivores, carnivores and also other omnivores for energy.
As mentioned in the title, we (the living organisms) all totally depend on the plants. The fundamental issue here is about energy. Energy creates and sustains life. Plants have the unique ability to turn solar energy into chemical energy, using a process we term âphotosynthesisâ. No other organisms can, so we all depend on the plants to start