Greeting

That's how two separate miracles happen within a period of time less than a second, which we refer to as "seeing" and "recognising".
The input that arrives in hundreds of millions of light particles reaches the mind of the person, is processed, compared to the memory and enables the man to recognise his friend.
A greeting follows recognition. A person deduces the reaction to be given to acquaintances from within the memory cells in less than a second. For example, he determines that he needs to say "greetings" upon which the brain cells controlling facial muscles will command the move that we know as a "smile". This command is similarly transferred through nerve cells and triggers a series of other complicated processes.
Simultaneously, another command is given to the vocal cords in the throat, tongue and the lower jaw and the "greetings" sound is produced by the muscle movements. Upon release of the sound, air molecules start travelling towards the man to whom the greeting is sent. The auricle gathers these sound waves, which travel at approximately twenty feet (six metres) per one fiftieth of a second.

The auricle is designed to collect and focus sounds into the auditory canal. The inside surface of the auditory canal is covered with cells and hairs that secrete a thicle waxy product to protect the ear against external dirt. At the end of the ear canal towards the start of the middle ear is the eardrum. Beyond the eardrum there are three small bones called the hammer, anvil and stirrup. The eustachian tube functions to balance air pressure in the middle ear. At the end of the middle ear is the cochlea that has an extremely sensitive hearing mechanism and is filled with a special fluid.

The vibrating air inside both ears of that person rapidly travels to his middle ear. The eardrum, 0.30 inch (7.6 millimetre) in diametre, starts vibrating as well. This vibration is then transferred to the three bones in the middle ear, where they are converted into mechanical vibrations that travel to the inner ear. They then create waves in a special fluid inside a snail shell-like structure called the cochlea.
Inside the cochlea, various tones of sound are distinguished. There are many strings of varying thickness inside the cochlea just as in the musical instrument, the harp. The sounds of the man's friend literally play their harmonies on this harp. The sound of "greetings" starts from a low pitch and rises. First, the thicker cords are rattled and then the thinner ones. Finally, tens of thousands of little bar-shaped objects transfer their vibrations to the auditory nerve.
Now the sound "greetings" becomes an electrical signal, which quickly travels to the brain through the auditory nerves. This journey inside the nerves continues until reaching the hearing centre in the brain. As a result, in the person's brain, the majority of the trillions of neurons become busy evaluating the visual and audio data gathered. This way, the person receives and perceives his friend's greeting. Now he returns the greeting. The act of speaking is realised through perfect synchronisation of hundreds of muscles within a minute portion of a second: the thought that is designed in the brain as a response is formulated into language. The brain's language centre, known as Broca's area, sends signals to all the muscles involved.

THE TRAVELLING OF THE SOUND FROM EAR TO BRAIN It is He Who has created hearing, sight and hearts for you. What little thanks you show! (Surat al-Muminun: 78) The ear is such a complex wonder of design that it alone nullifies the explanations of the theory of evolution in regards to a creation based on "coincidence". The hearing process in the ear is made possible by a completely irreducibly complex system. Sound waves are first collected by the auricle (1) and then hit the eardrum (2). This sets the bones in the middle ear (3) vibrating. Thus sound waves are translated into mechanical vibrations, which vibrate the so-called "oval window" (4), which in turn sets the fluid inside the cochlea (5) in motion. Here, the mechanical vibrations are transformed into nerve impulses which travel to the brain through the vestibular nerves (6). There is an extremely complex mechanism inside the cochlea. The cochlea (enlarged figure in the middle) has some canals (7), which are filled with fluid. The cochlear canal (8) contains the "organ of corti" (9) (enlarged figure on far right), which is the sense organ of hearing. This organ is composed of "hair cells" (10). The vibrations in the fluid of the cochlea are transmitted to these cells through the basilar membrane (11), on which the organ of corti is situated. There are two types of hair cells, inner hair cells (12a)and outer hair cells (12b). Depending on the frequencies of the incoming sound, these hair cells vibrate differently which makes it possible for us to distinguish the different sounds we hear. Outer hair cells (13) convert detected sound vibrations into electrical impulses and conduct them to the vestibular nerve (14). Then the information from both ears meet in the superior olivary complex (15). The organs involved in the auditory pathway are as follows: Inferior colliculus (16), medial geniculate body (17), and finally the auditory cortex (18).34 The blue line inside the brain shows the route for high pitches and the red for low pitches. Both cochleas in our ears send signals to both hemispheres of the brain. As is clear, the system enabling us to hear is comprised of different structures that have been carefully designed in the minutest detail. This system could not have come into existence "step by step", because the lack of the smallest detail would render the entire system useless. It is, therefore, very obvious that the ear is another example of flawless creation.

First, the lung provides "hot air". Hot air is the raw material of speech. The primary function of this mechanism is the inhalation of oxygen-rich air into the lungs. Air is taken in through the nose, and it travels down the trachea into the lungs. The oxygen in the air is absorbed by the blood in the lungs. The waste matter of blood, carbon dioxide, is given out. The air, at this point, becomes ready to leave the lungs.
The air returning from the lungs passes through the vocal cords in the throat. These cords are like tiny curtains, which can be "drawn" by the action of the small cartilages to which they are attached. Before speech, the vocal cords are in an open position. During speech they are brought together and caused to vibrate by the exhaled air passing through them. This determines the pitch of an individual's voice: the tenser the cords, the higher the pitch.
The air is vocalised by passing through the cords and reaches to the surface via the nose and mouth. The person's mouth and nose structure adds personal properties unique to him. The tongue draws near to and away from the palate and the lips take various shapes. Throughout these processes, many muscles work at great speed.35
The person's friend compares the sound he hears to others in his memory. By comparing, he can immediately tell if it is a familiar sound. Therefore, both parties recognise and greet each other.

The three bones in the middle ear function as a bridge between the eardrum and the inner ear. These bones, which are connected to one another by joints, amplify sound waves, which are then transmitted to the inner ear. The pressure wave that is created by the contact of the stirrup with the membrane of the oval window travels inside the fluid of the cochlea. The sensors triggered by the fluid start the "hearing" process.

All the above takes place during two friends noticing and greeting one another. All of these extraordinary processes happen at incredible speeds with stunning precision, of which we are not even aware. We see, hear and speak so very easily as if it is a very simple thing. However, the systems and processes that make them possible are so unimaginably complex.

In order to facilitate speech, not only do the vocal cords, nose, lungs and air passages have to work in harmony, but also the muscle systems that support these organs. Sounds created during speech are produced by air passing through the vocal cords.	Vocal cords are comprised of flexible cartilages tied to muscles on the skeleton. When the muscles are at rest, the cords are open (left). The cords close during speech (below). The tenser the cords, the higher the pitch.

The operation of the vocal cords has been photographed by means of high-speed cameras. All of the different positions seen above take place within less than one tenth of a second. Our speech is made possible through the flawless design of the vocal cords.

This complex system is full of examples of unparalleled design that the theory of evolution cannot explain. The origins of vision, hearing and thinking cannot be explained by the trust of evolutionists in "coincidences". On the contrary, it is obvious that all of them have been created and given to us by our Creator. While the human cannot even understand the working mechanism of systems that enable him to see, hear and think, the infinite wisdom and power of Allah Who created all these from nothing is apparently obvious.
In Qur'an, Allah invites humans to ponder this and to be thankful:

Allah brought you out of your mothers' wombs knowing nothing at all, and gave you hearing, sight and hearts so that perhaps you would show thanks. (Surat an-Nahl: 78)