Questions

Skimming is the removal of any material or particles that are floating on the surface. Hence, Removal of oil and grease from sewage - waste water is called as skimming.

The design plans for the U-shaped skyscraper ‘The Big Bend’ in New York, hailed as the world’s longest building, have been revealed. The 4,000-foot long building will feature an elevator system that can travel in curves, horizontally and in loops.

Brazil is one example of a closed economy in the given options. 

A closed economy is one that has no trade activity with outside economies. A closed economy is self-sufficient, which means no imports come into the country and no exports leave the country. A closed economy's intent is to provide domestic consumers with everything they need from within the country's borders.

An atom is composed of three subatomic particles. They are ::

1) Electron (-vely charged particle)

2) Proton (+vely charged particle)

3) Neutron (No charge particle)

Hence, Neutron is the subatomic particle which has no charge.