The city of Los Angeles released 96 million "shade balls" into the Los Angeles Reservoir. These will serve to shield the water from the sun's heat in order to reduce evaporation and prevent algal and bacterial growth so no toxic substances are produced in the water. The balls reduce evaporation by 85%-90% so will save a lot of water yearly.
I don really know why but it never made sense to me
Answer:
A small metallic core of high density with one quarter of its mass composed of water and ice.
Explanation: