Questions

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.

A Subquery or Inner query or a Nested query is a query within another SQL query and embedded within the WHERE clause.

Subqueries are most frequently used with the SELECT statement. The basic syntax is as follows::

SELECT column_name [, column_name ]
FROM table1 [, table2 ]
WHERE column_name OPERATOR
(SELECT column_name [, column_name ]
FROM table1 [, table2 ]
[WHERE])

A subquery is used to return data that will be used in the main query as a condition to further restrict the data to be retrieved.

Subqueries can be used with the SELECT, INSERT, UPDATE, and DELETE statements along with the operators like =, <, >, >=, <=, IN, BETWEEN, etc.

There are a few rules that subqueries must follow −

1. Subqueries must be enclosed within parentheses.

2. A subquery can have only one column in the SELECT clause, unless multiple columns are in the main query for the subquery to compare its selected columns.

3. An ORDER BY command cannot be used in a subquery, although the main query can use an ORDER BY. The GROUP BY command can be used to perform the same function as the ORDER BY in a subquery.

4. Subqueries that return more than one row can only be used with multiple value operators such as the IN operator.

5. The SELECT list cannot include any references to values that evaluate to a BLOB, ARRAY, CLOB, or NCLOB.

6. A subquery cannot be immediately enclosed in a set function.

7. The BETWEEN operator cannot be used with a subquery. However, the BETWEEN operator can be used within the subquery.

The capital of India shift from Kolkata to New Delhi in the year 1911.

Let the missing numbers be x, y, a and b

x + y = 8 ---- (1)
a - b = 6 ---- (2)
x + a = 13 --- (3)
y + b = 8 ---- (4)

2x + a + y = 21 --- From (1 & 3)
a + y = 14 ----  From (2 & 4)

Substitute (2 & 4) in (1 & 3)

2x + 14 = 21
2x = 7
x = 3.5

From (1) ---> 3.5 + y = 8
=> y = 8 - 3.5 = 4.5

a + y = 14 => a = 14 - y = 14 - 4.5 => a = 9.5
From (4) ---- y + b = 8 => b = 8 - y = 8 - 4.5 = 3.5

Hence,
x = 3.5
y = 4.5
a = 9.5
b = 3.5

The difference between Greenwich Mean Time & Indian Standard Time is 5 1/2 hours.

The meanings of the given words are as follows:
Histrionic: excessively theatrical or dramatic in character or style
Melodramatic: characteristic of melodrama, especially in being exaggerated or overemotional
Theatrical: exaggerated and excessively dramatic
Conscientious: wishing to do one's work or duty well and thoroughly
Diligent: having or showing care and conscientiousness in one's work or duties
Tenacious: tending to keep a firm hold of something; clinging or adhering closely
Retentive: (of a person's memory) effective in retaining facts and impressions
Thrive: (of a child, animal, or plant) grow or develop well or vigorously
Tussle: a vigorous struggle or scuffle, typically in order to obtain or achieve something
Pertinent: relevant or applicable to a
particular matter; apposite Appropriate: suitable or proper in the circumstances
Therefore, it can be observed that option  i.e. ‘melodramatic, theatrical’ forms a synonym- synonym pair of ‘histrionic’.