Questions

Primary productivity refers to plants that make their own food using sunlight, water and availability of nutrients. Hence, they are not limited by time.

Proxima Centauri is the nearest star to the Earth.

The Theme of National Press Day 2017 is "Challenges before media".

Sodium hydroxide, also known as lye and caustic soda, is an inorganic compound with the formula NaOH. It is a white solid ionic compound consisting of sodium cations Na+ and hydroxide anions OH−.

Properties:

1. It is highly soluble in water, and readily absorbs moisture and carbon dioxide from the air.

2. NaOH is insoluble in ether and other non-polar solvents.

3. It is an odorless compound.

Uses:

Sodium hydroxide is used in many industries: in the manufacture of pulp and paper, textiles, drinking water, soaps and detergents, and as a drain cleaner.

Black

Rainfall and addition of fresh water from rivers reduce salinity neat the coasts.

Fossil fuels energy source generates the least greenhouse gases. Of them, i.e, oil, natural gas and coal, natural gas source generates the least greenhouse gases.