The option D is true, which says the weasels' population is stable, because during this time a similar number of weasels have died as have been born.
Weasels are small mammals with long bodies and necks, short legs and small heads. They are a carnivorous animal that has sharp, pointed canine teeth which are used for biting and shearing flesh.
So if the scientist record the number of weasels in this ecosystem every year for 30 years and if she's noticing that average number of weasels remains same even after 100 new babies, then the population will be stable as similar number of weasels have died as have been born.
Hence, option D is true.
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