Which is regulated as a result of dam building?

Answer Beavers build Dams for food storage and protection. They build a dam tomake an artificial lake, and then they proceed to build their lodge nearby. Thedeeper water in a dam allows the beaver to travel near its home protected fromother animals and predators. After the dam is built, the beaver will also digchannels leading away from the new dam, to create safe transport channels forwhen it is gathering more wood to continue building its dam and lodge. Once itslodge and dam are built, the beaver will proceed to gather smaller pieces ofwood, and take it to the deep bit of the new lake directly next to the dam, andwill poke the wood into the mud. The cold water down there helps the wood staymuch fresher for longer. I have observed that beavers in the Rocky Mountainslove to eat the bark off of the Aspen trees. To get the bark, they must fell thetrees. As they use the trees closest to their beaver made lake, they get furtherand further away from the protection of the water of their dams. They then usethe logs or limbs (they have already eaten the bark) to make the dam higher andpush the water back to the edge of the aspen grove little by little. This is sothey can reach the water quickly when a predictor comes around.There is also astudy of dam building beavers being serinaded by the sound of running water (viarecording) in each case the beavers cover the speakers by the next day tosilence the noise. I don't think it because of the sound as much as it is toprevent their predictors from using the sound to sneak up on them unnoticed.
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Which of the following did you identify correctly