Goldilock region is the space which is neither too hot nor too cold and has conditions which are a must for life. So the Goldilock zone is a habitable zone.
Salinity is directly positively related to seawater density.On an average, seawater density increases with increasing salinity and vice versa.E.g. Density of pure water is 1.00 g/cm3 and density of water with 35% salinity is 1.028 g/cm3.
The zebrafish is a freshwater fish belonging to the minnow family. It is native to South Asia, it is a popular aquarium fish, frequently sold under the trade name zebra danio. It belongs to India and Sri Lanka.