Question Discussion & Solution

Concept:

The GROUP BY statement groups rows that have the same values into summary rows, like "find the number of customers in each country".

The GROUP BY statement is often used with aggregate functions (COUNT, MAX, MIN, SUM, AVG) to group the result-set by one or more columns.

GROUP BY Syntax

SELECT column_name(s)
FROM table_name
WHERE condition
GROUP BY column_name(s)
ORDER BY column_name(s);

The ORDER BY keyword is used to sort the result-set in ascending or descending order.

The ORDER BY keyword sorts the records in ascending order by default. To sort the records in descending order, use the DESC keyword.

ORDER BY Syntax

SELECT column1, column2, ...
FROM table_name
ORDER BY column1, column2, ... ASC|DESC;

Four members: A, B, C, D

Using the symbols in the table given below, we can draw the following family tree:

1) B is the husband of A

2) C is the sister of B

3) D is the brother of A

Hence, C is D’s brother-in-law's sister.

The correct answer is Sunderban Delta.

• Sunderban Delta is the largest delta in India.

Key Points

• Sunderbans has spread over 1330.10 sq. km.
• It is formed by the Ganga and Brahmaputra rivers in West Bengal and Bangladesh. 
• Sundarbans is also known for the mangrove forest which is one of the largest such forests in the world.
• Sundarbans was included in the World Heritage site in 1987.
• East Flowing Rivers are known as Delta forming rivers
  • East flowing rivers do not form estuaries.
  • East flowing rivers fall in the Bay of Bengal.

Additional Information

• A delta is a depositional feature of a river which is formed at the mouth of the river. 
• Largest River without is Delta Narmada and Tapti.

The correct option is 2 i.e. Sodium Carbonate

Key Points

• Sodium Carbonate is also known as washing soda it is a salt of carbonic acid.
• Sodium carbonate can be manufactured by Solvay's process.
• It is used for treating hard water and industrial detergent mixtures.
• The aqueous solution of sodium carbonate is alkaline.
• Calcium Sulphate exists in the forms of white solids and is not soluble in water.
• Plaster of Paris and Gypsum are its hydrates.

The correct answer is Sodium carbonate.

Key Points

• A toothpaste is defined as a semi-solid material for removing naturally occurring deposits from teeth and is supposed to be used simultaneously with a toothbrush.
• Toothpaste generally contains the following components:
  • Water (20–40%)
  • Abrasives (50%) including aluminum hydroxide, calcium hydrogen phosphates, calcium carbonate, magnesium carbonate, silica, and hydroxyapatite.
  • Fluoride (usually 1450 ppm) mainly in the form of sodium fluoride.