Questions

Footsteps. 

Yes, as you walk forward, you will leave the footstep behind you.

Prices do not reflect the full social cost of production is an example of Market failure.

A market failure occurs when the supply of a good or service is insufficient to meet demand. This results in an inefficient distribution of resources among market participants.

It also occurs if externalities are not accounted for.

If a firm fails to maximize its profits this is not a general market failure.

Usain Bolt is branded as "Fast Man on Earth".

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.

These can not be edited once the account is set up.

Government appointed former Canara Bank MD & CEO Rakesh Sharma as the new MD & CEO of IDBI Bank for the tenure of six months. Prior to him B. SRiram was the MD & CEO of IDBI Bank and he retired on September 30, 2018.

Muḥammad ibn Mūsā al-Khwārizmī, formerly Latinized as Algorithmi,was a Persianscholar who produced works in mathematics, astronomy, and geography under the patronage of the Caliph Al-Ma'mun of the Abbasid Caliphate.

He also developed the concept of the algorithm in mathematics, which is why some have called him the "grandfather of computer science".

His name gave rise to the terms algorism and algorithm.

Brazil is one example of a closed economy in the given options. 

A closed economy is one that has no trade activity with outside economies. A closed economy is self-sufficient, which means no imports come into the country and no exports leave the country. A closed economy's intent is to provide domestic consumers with everything they need from within the country's borders.