Answer:
they must complete for essential resources.
Step-by-step explanation:
In all environments, organisms must compete for essential resources because the quantities of these resources are limited. Examples of essential resources include food, water, sunlight, and shelter. Also, every population must interact with and is linked, directly or indirectly, with many others. For example, some organisms are able to produce their own food, while others must consume other organisms in order to acquire energy.