The Earth has four major systems or spheres. These systems are

 1. The geosphere,

 2. The hydrosphere,

 3. The atmosphere, and 

4. The biosphere.

The biosphere is the system where we belong.

Number of square units in 13 by 9 is given by the area it forms with length and breadth as 13 & 9

Area = 13 x 9 = 117

Hence, number of square units in 13 by 9 is 117 sq.units.

'M' is used as a unit of molarity and stands for mole per litre i.e, number of moles of solute per liter of solution.

Primary succession is the orderly and predictable series of events through which a stable ecosystem forms in a previously uninhabited region. Primary succession occurs in regions characterized by the absence of soil and living organisms.

Enzymes are protein macromolecules. Enzymes are almost always made of proteins only. Proteins are large biopolymer molecules that are made up of repeating monomer units called amino acids. There are 20 different common amino acids that make up proteins like enzymes. Of these, nine amino acids are essential, which means you must get them from your diet.

Enzymes catalyze chemical reactions in biological systems. This means that they speed up the rate of the reaction.

VOIP is an acronym for Voice Over Internet Protocol, or in more common terms phone service over the Internet.

Voice over Internet Protocol is a category of hardware and software that enables people to use the Internet as the transmission medium for telephone calls by sending voice data in packets using IP rather than by traditional circuit transmissions of the PSTN.

Here in the given options, Skype is the only voice service that enables us to talk over internet.

Laissez-faire is simply a way to describe a government's hands-off approach to economic policies. This approach was particularly prevalent in the United States at the turn of the 20th century, which led to numerous issues within American manufacturing.

There are many outcomes of laissez-faire economic policies. Some of the outcomes of laissez-faire economics were:

* Businesses pay workers low.

* Pollution of air and water.

* Poverty traps that cannot be escaped through free choice. 

* General glut that results from overproduction or underconsumption

* Monopoly power that emerges naturally in the market and allows businesses to exploit consumers. 

* Exploitation of the working class that pushes wages down to subsistence and compels laborers to work in harsh and unsafe conditions. 

* External economies that generate situations where desirable goods are underproduced on the market, and undesirable goods are overproduced on the market. 

* Public goods that are not supplied by the market due to free-rider problems.