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 producers, plants play a part in the way the ecosystem functions, creating a world that supports life. Plants provide food for the masses. From elephants to mice, animals eat grass, nuts, berries and twigs to fuel the body and activities. Meat eaters dine on grazers.