If ice were more dense than water, it would freeze and sink over and over until the entire lake was frozen. ... This same process occurs in the fall as the surface water cools and becomes more dense; it will sink and cause the same movement or turnover of the lake's water.
In 2008 we started to recycle more often and produced less waste. This is mainly due to the fact that global warming was starting to spread to the public.
5 grams will be left. After the first 1000 years, there will be half of 20 left, or 10. After 2000 years, half of 10 will remain, which is 5.