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.
Pollination can also occur within the same flower. Most flowering plants (90 percent) depend on animals to make the vital pollen-grain delivery. The remaining flowering plants rely on wind and some-times splashing raindrops to ferry pollen, but this is a less precise method. Pollinating animals do the job for a reward: food, usually in the form of nectar.