Questions

Africa - 54 countries

South America - 12 countries

Antarctica - 0 countries

Europe - 43 countries.

Hence, Antarctica continent has the least countries.

Database provides necessary means to achieve this abstraction. By structure of a database we mean the data types, relations, and constraints that should hold on the data.

The area in which two types of air masses meet is called Front. There are two types of fronts. They are 

1) Cold front

2) Warm front

When a cold air mass pushes a warm air mass, it is called as Cold front. Similarly, when a warm air mass pushes the cold air mass, it is called as warm front.

A neuron or nerve cell is a cell that carries electrical impulses. Neurons are the basic units of the nervous system and its most important part is the brain. Every neuron is made of a cell body (also called a soma), dendrites and an axon. Dendrites and axons are nerve fibres.

The gap between two communicating neurons is termed Synaptic cleft.

A cumulene is a hydrocarbon with three or more cumulative double bonds. They are analogous to allenes, only having a more extensive chain. The simplest molecule in this class is butatriene, which is also called simply cumulene.

The carbons on the ends are sp² hybridized, with a p-orbital for the 'second' bond in the double bond with their neighboring carbons.

They have those sp² orbitals overlapping with the s from the hydrogen, and they have a p overlapping in the pi bond with the neighboring carbon. They also have a sigma bond with the neighboring carbon I'll get to.

The middle carbons each have two pi bonds with their neighbors, leaving sp hybridiaztion for the rest. So they have sp/sp² with the end carbons, and sp/sp with each other. (And they also have p/p in the pi bonds).

All orbital overlappings in Cumuene are :

* s/sp²

* p/p

* sp/sp²

* sp/sp