Evidence Explain the sudden decrease in,
density when water is at 0°C as shown on
the graph.

Explanation:

The density of pure water ice at 0°C is 0.9168 g/ml, nearly 9% lighter than liquid water at 0°C, which has a density of 0.99987 g/ml 14. ... This drop in density occurs because the hydrogen bonds in water create an open hexagonal lattice, leaving space between the molecules 42.

the answers would be

the first one and the second one

the density of gold = 19.3 g/cm3

the relation between density and mass and volume is

density = mass / volume

given :

mass of gold = 13 g

density = 13g / volume = 19.3

volume = 13 /19.3 = 0.67 cm^3

thus volume of gold nugget = 0.67 cm^3