Important Questions: Water - Class 7 MCQ

During these Moon phases, the solar tide coincides with the lunar tide because the Sun and the Moon are aligned with Earth, and their gravitational forces combine to pull the ocean's water in the same direction. These tides are known as spring tides or king tides.

About 71 percent of the Earth's surface is water-covered, and the oceans hold about 96.5 percent of all Earth's water. Water also exists in the air as water vapor, in rivers and lakes, in icecaps and glaciers, in the ground as soil moisture and in aquifers.

Warm ocean currents flow away from the equatorial region on the western side of ocean basins. The Gulf Stream in the North Atlantic and the KuroshioCurrent in the North Pacific are examples of warm currents. Of all the warm currents, the Gulf Stream has been studied most extensively.

Ocean currents are primarily horizontal water movements. Ocean currents flow for great distances, and together, create the global conveyor belt which plays a dominant role in determining the climate of many of the Earth's regions.

The Labrador Current is a cold current in the North Atlantic Ocean which flows from the Arctic Ocean south along the coast of Labrador and passes around Newfoundland, continuing south along the east coast of Nova Scotia. It is a continuation of the West Greenland Current and the Baffin Island Current.

Seawater is water from a sea or ocean. On average, seawater in the world's oceans has a salinity of approximately 3.5%, or 35 parts per thousand. 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.

The River Nile is the longest river in the world. It measures 6,695 kilometres from its source in Burundi, along the White Nile, to its delta on the Mediterranean Sea. Officially, the shortesr river is the D River, Oregan, USA, which is just 37 metres long.