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.
Plants make their own food and are called autotrophs. Animals must consume other organisms and are called heterotrophs. This difference classiï¬ es plants and animals into two separate groups.Method of reproduction can be used to classify organisms into even smaller groups. The two main reproductive methods are asexual and sexual reproduction.