Questions

Labor unions are associations of workers who pursue common objectives. Workers use this platform to bargain collectively on behalf of the majority of workers.

The red blood corpuscles  or erythrocytes usually carry antigens and there are two types of antigens. The A group persons have antigen A in their red corpuscles and the B group have antigen B in their red corpuscles. The AB group person have both antigen A and antigen B in their erythrocytes. The 'O' group persons have no antigens in their red corpuscles.

The first of the four stages of coal formation is lignite coal.

There are four stages of coal formation:

1. Peat,

2. Lignite,

3. Bituminous and

4. Anthracite.

The bacteria has removed a large portion of the other constituents of the plant matter and left around 25 to 34 percent.

The letter 'X' resembles the same as the tool AXE in sounding.

Hence, the alphabet X is a tool.

RST 4.5 is called as TRAP.

A Carpet is the pet which always stays on the floor.

Candidate Key – A Candidate Key can be any column or a combination of columns that can qualify as unique key in database. There can be multiple Candidate Keys in one table. Each Candidate Key can qualify as Primary Key. 

Primary Key – A Primary Key is a column or a combination of columns that uniquely identify a record. Only one Candidate Key can be Primary Key.

• One needs to be very careful in selecting the Primary Key as an incorrect selection can adversely impact the database architect and future normalization. For a Candidate Key to qualify as a Primary Key, it should be Non-NULL and unique in any domain.