C. Parasitism because fleas don’t offer any purpose but to hurt the dog
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Answer:The most important part of the cycle is bacteria. Bacteria help the nitrogen change between states so it can be used. When nitrogen is absorbed by the soil, different bacteria help it to change states so it can be absorbed by plants. Animals then get their nitrogen from the plants.
Answer: Down syndrome and cystic fibrosis
B. 245 million
from the end of Carboniferous Period to the beginning of the Triassic period
