Oceanography and Hydrology

Larger pieces of rock that are encrusted in till or deposited on the surface are called "glacial eratics". They range in size from pebbles to boulders, but as they are often moved great distances, they may be drastically different from the material upon which they are found.

Sea beaches are not the erosional feature of sea waves. They are formed due to the depositional activities of sea waves.

Scientific estimates of the total solid matter transported by rivers into the oceans are generally cited around 300 million tonnes annually. This is a specific factual figure often found in environmental science textbooks.

Sea forts (Jal-durg) were constructed in coastal or island locations, using the surrounding water as a natural moat for protection.

It is known as crystallization - because salt is obtained in crystal form.

On evaporation of seawater in shallow pools, salt along with impurities remain behind. Impured salt is taken in a tank and its saturated solution is prepared. In a saturated solution of salt, HCl vapours are passed. Chloride ions being common to both, it's concentration increases, and NaCl gets precipitated which is free from impurities.

Tsunamis are primarily caused by underwater earthquakes, volcanic eruptions, or landslides that displace a large volume of water.

Mangroves act as a natural barrier, absorbing the energy of incoming waves and reducing the impact of tsunamis on the coastline.

A flood is an overflow of water that submerges land that is usually dry. Flooding may occur as an overflow of water from water bodies, such as a river, lake, or ocean, in which the water overtops or breaks levees, resulting in some of that water escaping its usual boundaries, or it may occur due to an accumulation of rainwater on saturated ground in an areal flood. While the size of a lake or other body of water will vary with seasonal changes in precipitation and snow melt, these changes in size are unlikely to be considered significant unless they flood property or drown domestic animals.

Approximately 97 percent of Earth's water is saline, found in the oceans. Among the options provided, 93.7 percent is the closest accepted value in many textbooks.

An estuary is a partially enclosed coastal body of brackish water with one or more rivers or streams flowing into it, and with a free connection to the open sea.

In the ocean, carbon dioxide dissolves in water to form carbonic acid, which then dissociates into bicarbonate and carbonate ions, with bicarbonate being the most abundant form.

The process by which water continually changes its form and circulates between oceans, atmosphere and the land is called the water cycle.

The rhythmic rise and fall of the ocean twice in a day is called a tide. Tides are caused by the strong gravitational pull exerted by the sun and the moon on the earth's surface.

The continental shelf is shallow and rich in mineral and energy resources, making it highly valuable for mining activities such as oil and gas extraction.