A variable provides us with named storage that our programs can manipulate. Each variable in C++ has a specific type, which determines the size and layout of the variable's memory the range of values that can be stored within that memory and the set of operations that can be applied to the variable.

The name of a variable can be composed of letters, digits, and the underscore character. It must begin with either a letter or an underscore. Upper and lowercase letters are distinct because C++ is case-sensitive −

Basic types of variables:

1. bool

Stores either value true or false.

2. char

Typically a single octet (one byte). This is an integer type.

3. int

The most natural size of an integer for the machine.

4. float

A single-precision floating point value.

5. double

A double-precision floating point value.

6. void

Represents the absence of type.

7. wchar_t

A wide character type.

FALSE. Each hemoglobin molecule can transport four molecules of oxygen.

Hemoglobin, or Hb, is a protein molecule found in red blood cells (erythrocytes) made of four subunits: two alpha subunits and two beta subunits. Heme the component of hemoglobin responsible for binding oxygen consists of an iron ion that binds oxygen and a porphyrin ring that binds the globin molecules, one molecule binds one molecule of oxygen and can bind up to four oxygen molecules.

Only H and Br form Polar Covalent Bond.

Covalent bonding:

Covalent bonding occurs when pairs of electrons are shared by atoms. Atoms will covalently bond with other atoms in order to gain more stability, which is gained by forming a full electron shell. By sharing their outer most (valence) electrons, atoms can fill up their outer electron shell and gain stability.

1. Polar Covalent Bond

2. Nonpolar Covalent Bond

1. Polar Covalent Bond:

A Polar Covalent Bond is created when the shared electrons between atoms are not equally shared. This occurs when one atom has a higher electronegativity than the atom it is sharing with. The atom with the higher electronegativity will have a stronger pull for electrons (Similiar to a Tug-O-War game, whoever is stronger usually wins). As a result, the shared electrons will be closer to the atom with the higher electronegativity, making it unequally shared.

2. Nonpolar Covalent Bond:

A Nonpolar Covalent Bond is created when atoms share their electrons equally. This usually occurs when two atoms have similar or the same electron affinity. The closer the values of their electron affinity, the stronger the attraction. This occurs in gas molecules; also known as diatomic elements. Nonpolar covalent bonds have a similar concept as polar covalent bonds; the atom with the higher electronegativity will draw away the electron from the weaker one.

Here H and H and N and N form Non-polar covalent bonds. Na and Br form the ionic bond.

Among the given options, mud is not an aerosol.

An aerosol is a suspension of fine solid particles or liquid droplets, in the air or another gas. Aerosols can be natural or anthropogenic. Examples of natural aerosols are fog, dust, forest exudates and geyser steam. Examples of anthropogenic aerosols are haze, particulate air pollutants, and smoke.

The main simple sugar found in fruit is Fructose. Glucose is found naturally occurring in fruits and other plants. But fructose is sweeter than glucose and can give you more energy. That's why a piece of fruit in the morning will give you more energy than a cup of coffee!

Fructose is what gives most fruits that sweet flavor and in combination with the acids present in certain fruits can give a pleasantly tangy flavor.

Poor people have Nothing

Rich people need Nothing

If you eat Nothing you die.

Hence, it is Nothing.

CDs are the least risky investment choice when compared to flipping, renting and bonds.

A certificate of deposit (CD) is a savings certificate with a fixed maturity date, specified fixed interest rate and can be issued in any denomination aside from minimum investment requirements. A CD restricts access to the funds until the maturity date of the investment. CDs are generally issued by commercial banks.

CDs are issued by the bank and are guaranteed by the government. So even if the bank goes bankrupt the investor's money is guaranteed to a certain extent.

Flipping and renting are subjected to market fluctuations while bonds are not insured.

Hierarchy is a system of ranking in which members of a particular society are ranked in an ascending order depending on various factors.

Hence, the term hierarchy refers to a power structure in which each member knows his or her own place.