Graphite is a covalent-network type of crystalline solid.

There are two main categories of solids.

1. Crystalline solids and

2. Amorphous solids.

Crystalline solids are those in which the atoms, ions, or molecules that make up the solid exist in a regular, well-defined arrangement.

There are four types of crystalline solids :

Ionic solids :— Made up of positive and negative ions and held together by electrostatic attractions. They’re characterized by very high melting points and brittleness and are poor conductors in the solid state. An example of an ionic solid is table salt, NaCl.

Molecular solids :— Made up of atoms or molecules held together by London dispersion forces, dipole-dipole forces, or hydrogen bonds. Characterized by low melting points and flexibility and are poor conductors. An example of a molecular solid is sucrose.

Covalent-network (also called atomic) solids :— Made up of atoms connected by covalent bonds; the intermolecular forces are covalent bonds as well. Characterized as being very hard with very high melting points and being poor conductors. Examples of this type of solid are diamond and graphite, and the fullerenes. As you can see below, graphite has only 2-D hexagonal structure and therefore is not hard like diamond. The sheets of graphite are held together by only weak London forces!

Metallic solids :— Made up of metal atoms that are held together by metallic bonds. Characterized by high melting points, can range from soft and malleable to very hard, and are good conductors of electricity.

From the given data,

18 snakes can eat 18 bananas in 18 hrs.

=> 1 snake can eat 1 banana in 18 hrs

=> 79 snakes can eat 79 bananas in 18 hrs.

Hence, 18 hrs.

The series number is found in both the upper right margin and the lower left margin. It is a sequence reference expressed either as a four-digit numeral (1125) or as a letter, followed by a three- or four-digit numeral (M661, T7110).

Capital refers to buildings and equipment i.e, goods which are used by workers to produce other goods such as machinery, land, ...

Capital has a number of related meanings in economics, finance, and accounting.

In economics, Capital comprises one of the four major factors of production, the others being land, labor, and entrepreneurship.

In finance and accounting, capital generally refers to financial wealth, especially that used to start or maintain a business.

The first indicator of an approaching thunderstorm is a buildup of dark clouds.

A thunderstorm is a storm with lightning and thunder; it is usually produced by heavy rain, gusty wind, and the cumulonimbus cloud. The thunderstorm is made up of moisture, unstable air and lift.

The Capital city of Ethiopia is Addis Ababa.

Countries and Capital cities ::

Angola  -  Launda

Burundi  -  Bujumbura

Chile  -  Santiago