Explain why no ecosystem operates independently. give an example of an interaction between different ecosystems that could be seen in a food chain or a food web.

In every ecosystem, there are different organisms that interact with each other in a particular environment.  

The components of an ecosystem interact and interrelate with the ones that form part of another. Every ecosystem is related to another one.  

For example, in a food chain, a bird eats a fish, both animals belong to different ecosystems, but they are connected with each other.

a tetrad is the foursome during meiosis made by two homologous chromosomes that have each already replicated into a pair of sister chromatids.

producers: apple trees, potatoes, carrots, grains, acorns, cabbage, grass, corn, lettuce

consumers: deer, mice, rabbits, chickens, squirrels, horses, worms, cows

predators: eagles, frogs, wolves, owls