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.

The project initiator or sponsor should be at a level that is appropriate to funding the project. They will either create the project charter or delegate that duty to the project manager.

Projects are authorized by someone external to the project such as a sponsor, PMO or portfolio steering committee.

Distance between two Consecutive Crests or two Consecutive Troughs is called Wavelength. But the distance between crest and adjacent trough is half the wavelength.

That is the distance between adjacent crest and trough is called Half the wavelength.

Robert Brown, Scottish botanist, Discovered The Nucleus of a Cell in 1831, London. When Brown was studying orchids under microscope when he observed an opaque area, which he called the "Areola" or "Nucleus", in the cells of the flower's outer layer.

The nucleus was also described by Franz Bauer in 1804 but in detail Robert Brown made it in 1831.

Let the rquired number be 'P'

According to the question,

$$\begin{gathered} 100 x P100 = 20 \\ => P = 20 x 100100 = 20 \end{gathered}$$

Hence, 100 percent of the number 20 is 20.

Now, you can also try for

20 percent of what number is 100

$$\begin{gathered} 20 x P100 = 100 \\ => P = 100 x 10020 = 500 \\ => P = 500 \end{gathered}$$

Hence, 20 percent of the number 500 is 100.

Consent of the People means the Majority of People, as expressed by votes in elections.

Consent of the governed refers to the idea that a government's legitimacy and moral right to use state power is only justified and lawful when consented to by the people or society over which that political power is exercised.

Cross Contamination ::

Cross Contamination is nothing but a contamination in a cross way i.e, when a bacteria on a kitchen tool transfers to food via direct contact. Two of the most common kitchen tools usually tend to be a knife or a cutting board. However, it is not just bacteria that gets carried from one place to another — it could also be a virus also.

Cross Contamination is prevented by the following tips ::

1. Use separate equipment

2. Clean and sanitize all work surfaces

3. Remind employees to wash their hands

4. Purchase prepared food

5. Implement a personal hygiene program.

Helium has the highest First Ionization Energy in the Noble Gases group.

Ionization Energy ::

Ionisation energy is the energy required to remove one mole of electrons from one mole of gaseous atoms. Atoms are more stable when they have full valence shells.

Noble Gases have a very stable electron configuration, therefore, they have the highest amount of ionization energy within their periods. It decreases down a family because electrons farther from the nucleus are easier to remove.

Ionization Energy levels of Noble Gases group in Descending Order :: He, Ne, Ar, Kr, Xe, Rn