If the predator that feeds off the dart frogs goes extinct or migrates to a different area then the dart fronts will have a much larger population. This means that the resources the dart frogs rely on will start to deminish and their prey will have smaller numbers
In order for plants to assimilate nitrogen directly into their system, the nitrogen must be in the form of nitrates. Nitrogen in the air and ammonia from decayed matter in the soil is converted to ammonium by decomposers and nitrogen-fixing bacteria. The ammonium is further nitrified to nitrates by nitrifying bacteria. Finally, the nitrates can then absorbed by the plants.
The answer is Chordates
Most of the chordates have a symmetrical bilateral body which differentiated into head, trunk and tail
The example of chordates are parrot, penguin, horse , squirell, clown fish ( the one in finding nemo), sharks, etc
