Questions

When water is cooled from 4°C to 0°C, its density decreases.

When water cools from 4°C to 0°C, ice crystals begin to form because the water is approaching its freezing point. When water freezes, the water molecules form a lattice that increases the volume. As a result, the density decreases. This is why ice will float on top of water; ice has a lower density than the water.

A search engine is a set of programs which enables users to search documents and files ihe world wide web.

Common search engines are Google, Yahoo, Bing,...

Roger Federer, a star tennis player won his 99th career title in his hometown, Switzerland.

The most important determinant of consumer spending is the level of income.