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.
Why do animals depend on plants. Plants give animals the food and shelter they need. Herbivores, which are plant eating animals, rely on plants to provide them with a regular source of food. They also provide shelter to may animals, both large and small.
The food chain of living things. Animals get their energy from food. Herbivores, like deer and hare, feed on plants. Carnivores, like lions and wolves, eat meat. Omnivores, which include pigs, bears, and humans, eat both plants and animals. In an ecosystem, all the organisms that depend on one another in order to eat form a food chain. Plants are at the bottom of this chain. They get their energy from the sun, which allows them to manufacture the substances they need for their development. Most animals depend directly or indirectly on plants.