Solution:
The average salt content is 35 gm. in a litre of seawater. This means that for every 1 litre (1000 mL) of seawater there are 35 grams of salts (mostly, but not entirely, sodium chloride) dissolved in it.

Solution:
Kiel Canal connects the North Sea with the Baltic sea. The canal was finished in 1895, but later widened, and links the North Sea at Brunsbüttel to the Baltic Sea at Kiel-Holtenau.

Solution:
The north flowing rivers of Siberia are not of much use for navigation mainly because The lower courses remain frozen for many months.

Solution:
With the population of around 500, European country Vatican City has smallest population in the world. Vatican City is the smallest country in the world, measuring just 0.2 square miles, almost 120 times smaller than the island of Manhattan. Situated on the western bank of the Tiber River, Vatican City's 2-mile border is landlocked by Italy.

Solution:
The largest archipelago in the world is Indonesia. It has 18000 islands in total.

Solution:
The world's largest reserves of petroleum are located in Russia. Russia is the world's largest producer of crude oil. It was the world's largest producer of crude oil including lease condensate and the third-largest producer of petroleum and other liquids (after Saudi Arabia and the United States) in 2014, with average liquids production of 10.9 million barrels per day.

Solution:
Pedology is a science of the study of Soils. Pedology is the scientific study of soils and their weathering profiles. Pedology deals with pedogenesis, soil morphology, and soil classification, while edaphology studies the way soils influence plants, fungi, and other living things.