Questions

Joseph Priestley and Carl Wilhelm Scheele both independently discovered oxygen in the year 1774, but Priestly is usually given credit for the discovery.

Adam's Bridge is the name of the bridge between India and Sri Lanka. It is also called as Rama Setu or Rama's Bridge.

General education policy is set by multiple levels of the government like Federal, state and local governments. 

Secondary succession means in an ecosystem renewal of itself after all or a portion has been destroyed.

After a forest fire, the whole forest had destroyed but after that again renewal of that forest is also an example of secondary succession.

A promise. 

The Promise made to somebody by you can be break but you cannot touch it.

3 + 5 + 6  = 151872

3x5, 3x6, Rev of (3x5 + 3x6 - 6) 

5 + 5 + 6  = 253094

5x5, 5x6, Rev of (5x5 + 5x6 - 6)

Similarly,

9x4 = 36

9x7 = 63

So 36 + 63 = 99

From 99 - 7 =  92

Reverse of 92=29

Hence, 9 + 4 + 7 =  366329.

A primary key is a special relational database table column or combination of columns designated to uniquely identify all table records. That is, A primary key is a column or set of columns in a table that uniquely identifies tuples (rows) in that table.

A primary key, also called a Primary Keyword.

Main Features Primary key are ::

It must contain a unique value for each row of data.

It cannot contain null values.