Please answer the following question: Information:  - In biological anatomy , commonly referred to as the mouth , under formal names such as the oral cavity , buccal cavity , or in Latin cavum oris , is the opening through which many animals take in food and issue vocal sounds . It is also the cavity lying at the upper end of the alimentary canal , bounded on the outside by the lips and inside by the pharynx and containing in higher vertebrates the tongue and teeth . This cavity is also known as the buccal cavity , from the Latin bucca ( `` cheek '' ) . Some animal phyla , including vertebrates , have a complete digestive system , with a mouth at one end and an anus at the other . Which end forms first in ontogeny is a criterion used to classify animals into protostome and deuterostome .  - Swallowing, sometimes called deglutition in scientific contexts, is the process in the human or animal body that makes something pass from the mouth, to the pharynx, and into the esophagus, while shutting the epiglottis. Swallowing is an important part of eating and drinking. If the process fails and the material (such as food, drink, or medicine) goes through the trachea, then choking or pulmonary aspiration can occur. In the human body the automatic temporary closing of the epiglottis is controlled by the swallowing reflex.  - Cheeks constitute the area of the face below the eyes and between the nose and the left or right ear. "Buccal" means relating to the cheek. In humans, the region is innervated by the buccal nerve. The area between the inside of the cheek and the teeth and gums is called the vestibule or buccal pouch or buccal cavity and forms part of the mouth. In other animals the cheeks may also be referred to as jowls.  - The domestic cat is a small, typically furry, carnivorous mammal. They are often called house cats when kept as indoor pets or simply cats when there is no need to distinguish them from other felids and felines. Cats are often valued by humans for companionship and for their ability to hunt vermin. There are more than 70 cat breeds, though different associations proclaim different numbers according to their standards.  - Taste, gustatory perception, or gustation is one of the five traditional senses that belongs to the gustatory system.  - Saliva is a watery substance formed in the mouths of animals, secreted by the salivary glands. Human saliva comprises 99.5% mostly water, plus electrolytes, mucus, white blood cells, epithelial cells (which can be used to extract DNA), glycoproteins, enzymes (such as amylase and lipase), antimicrobial agents such as secretory IgA and lysozyme. The enzymes found in saliva are essential in beginning the process of digestion of dietary starches and fats. These enzymes also play a role in breaking down food particles entrapped within dental crevices, thus protecting teeth from bacterial decay. Furthermore, saliva serves a lubricative function, wetting food and permitting the initiation of swallowing, and protecting the mucosal surfaces of the oral cavity from desiccation.  - The blood vessels are the part of the circulatory system that transports blood throughout the human body. There are three major types of blood vessels: the arteries, which carry the blood away from the heart; the capillaries, which enable the actual exchange of water and chemicals between the blood and the tissues; and the veins, which carry blood from the capillaries back toward the heart. The word "vascular", meaning relating to the blood vessels, is derived from the Latin "vas", meaning vessel. A few structures (such as cartilage and the lens of the eye) do not contain blood vessels and are labeled.  - The lungs are the primary organs of respiration in humans and many other animals including a few fish and some snails. In mammals and most other vertebrates, two lungs are located near the backbone on either side of the heart. Their function in the respiratory system is to extract oxygen from the atmosphere and transfer it into the bloodstream, and to release carbon dioxide from the bloodstream into the atmosphere, in a process of gas exchange. Respiration is driven by different muscular systems in different species. Mammals, reptiles and birds use their musculoskeletal systems to support and foster breathing. In early tetrapods, air was driven into the lungs by the pharyngeal muscles via buccal pumping, a mechanism still seen in amphibians. In humans, the primary muscle that drives breathing is the diaphragm. The lungs also provide airflow that makes vocal sounds including human speech possible.  - Mastication or chewing is the process by which food is crushed and ground by teeth. It is the first step of digestion, and it increases the surface area of foods to allow more efficient break down by enzymes. During the mastication process, the food is positioned by the cheek and tongue between the teeth for grinding. The muscles of mastication move the jaws to bring the teeth into intermittent contact, repeatedly occluding and opening. As chewing continues, the food is made softer and warmer, and the enzymes in saliva begin to break down carbohydrates in the food. After chewing, the food (now called a bolus) is swallowed. It enters the esophagus and via peristalsis continues on to the stomach, where the next step of digestion occurs.  - The nasal cavity (or nasal fossa) is a large air filled space above and behind the nose in the middle of the face. Each cavity is the continuation of one of the two nostrils.  - Taste buds contain the taste receptor cells, which are also known as gustatory cells. The taste receptors are located around the small structures known as papillae found on the upper surface of the tongue, soft palate, upper esophagus, the cheek and epiglottis. These structures are involved in detecting the five elements of taste perception: salty, sour, bitter, sweet and umami; through the combination of these elements we detect "flavors." A popular myth assigns these different tastes to different regions of the tongue; in reality these tastes can be detected by any area of the tongue. Via small openings in the tongue epithelium, called taste pores, parts of the food dissolved in saliva come into contact with the taste receptors. These are located on top of the taste receptor cells that constitute the taste buds. The taste receptor cells send information detected by clusters of various receptors and ion channels to the gustatory areas of the brain via the seventh, ninth and tenth cranial nerves.  - The ear is the organ of hearing and, in mammals, balance. In mammals, the ear is usually described as having three partsthe outer ear, middle ear and the inner ear. The outer ear consists of the pinna and the ear canal. Since the outer ear is the only visible portion of the ear in most animals, the word "ear" often refers to the external part alone. The middle ear includes the tympanic cavity and the three ossicles. The inner ear sits in the bony labyrinth, and contains structures which are key to several senses: the semicircular canals, which enable balance and eye tracking when moving; the utricle and saccule, which enable balance when stationary; and the cochlea, which enables hearing. The ears of vertebrates are placed somewhat symmetrically on either side of the head, an arrangement that aids sound localisation.  - The pharynx (plural: pharynges) is the part of the throat that is behind the mouth and nasal cavity and above the oesophagus and the larynx, or the tubes going down to the stomach and the lungs. The pharynx is an organ found in vertebrates and invertebrates, though the structure is not universally the same across all of those species.   - A nerve is an enclosed, cable-like bundle of axons (nerve fibers, the long and slender projections of neurons) in the peripheral nervous system. A nerve provides a common pathway for the electrochemical nerve impulses that are transmitted along each of the axons to peripheral organs.  - The buccal nerve (long buccal nerve) is a nerve in the face. It is a branch of the mandibular nerve (which is itself a branch of the trigeminal nerve) and transmits sensory information from skin over the buccal membrane (in general, the cheek) and from the second and third molar teeth. Not to be confused with the buccal branch of the facial nerve which transmits motor information to the buccinator muscle.  - Vertebrates comprise all species of animals within the subphylum Vertebrata (chordates with backbones). Vertebrates represent the overwhelming majority of the phylum Chordata, with currently about 64,000 species described. Vertebrates include the jawless fish and the jawed vertebrates, which include the cartilaginous fish (sharks and rays) and the bony fish.   - The larynx (plural larynges; from the Greek  "lárynx"), commonly called the voice box, is an organ in the neck of tetrapods involved in breathing, sound production, and protecting the trachea against food aspiration. It manipulates pitch and volume. The larynx houses the vocal cords, which are essential for phonation. They are situated just below where the tract of the pharynx splits into the trachea and the esophagus.  - In vertebrate anatomy, the throat is the anterior part of the neck, positioned in front of the vertebra. It contains the pharynx and larynx. An important section of it is the epiglottis, which is a flap separating the esophagus from the trachea (windpipe) preventing food and drink being inhaled into the lungs. The throat contains various blood vessels, pharyngeal muscles, the nasopharyngeal tonsil, the tonsils, the palatine uvula, the trachea, the esophagus, and the vocal cords. Mammal throats consist of two bones, the hyoid bone and the clavicle. The "throat" is sometimes thought to be synonymous for the isthmus of the fauces.  - The tongue is a muscular organ in the mouth of most vertebrates that manipulates food for mastication, and is used in the act of swallowing. It is of importance in the digestive system and is the primary organ of taste in the gustatory system. The tongue's upper surface (dorsum) is covered in taste buds housed in numerous lingual papillae. It is sensitive and kept moist by saliva, and is richly supplied with nerves and blood vessels. The tongue also serves as a natural means of cleaning the teeth. A major function of the tongue is the enabling of speech in humans and vocalization in other animals.  - Modern humans ("Homo sapiens", primarily ssp. "Homo sapiens sapiens") are the only extant members of Hominina tribe (or human tribe), a branch of the tribe Hominini belonging to the family of great apes. They are characterized by erect posture and bipedal locomotion; manual dexterity and increased tool use, compared to other animals; and a general trend toward larger, more complex brains and societies.  - Speech is the vocalized form of communication based upon the syntactic combination of lexicals and names that are drawn from very large (usually about 1,000 different words) vocabularies. Each spoken word is created out of the phonetic combination of a limited set of vowel and consonant speech sound units (phonemes). These vocabularies, the syntax which structures them, and their sets of speech sound units differ, creating many thousands of different, and mutually unintelligible, human languages. Most human speakers are able to communicate in two or more of them, hence being polyglots. The vocal abilities that enable humans to produce speech also enable them to sing.  - The stomach is a muscular, hollow, dilated part of the gastrointestinal tract that functions as an important organ in the digestive system. The stomach is present in many animals including vertebrates, echinoderms, insects (mid-gut), and molluscs. In humans and many other vertebrates it is involved in the second phase of digestion, following mastication (chewing).  - Blood is a body fluid in humans and other animals that delivers necessary substances such as nutrients and oxygen to the cells and transports metabolic waste products away from those same cells.  - The face is a central organ of sense and is also very central in the expression of emotion among humans and among numerous other species. The face is normally found on the anterior ("frontal", "rostral") surface of the head of animals or humans, although not all animals have faces. The face is crucial for human identity, and damage such as scarring or developmental deformities have effects stretching beyond those of solely physical inconvenience.  - The esophagus (American English) or oesophagus (British English) (/sfs/), commonly known as the food pipe or gullet, is an organ in vertebrates through which food passes, aided by peristaltic contractions, from the pharynx to the stomach. The esophagus is a fibromuscular tube, about 25 centimetres long in adults, which travels behind the trachea and heart, passes through the diaphragm and empties into the uppermost region of the stomach. During swallowing, the epiglottis tilts backwards to prevent food from going down the larynx and lungs. The word "esophagus" is the Greek word for "gullet".    After reading the paragraphs above, we are interested in knowing the entity with which 'mouth' exhibits the relationship of 'part of'. Find the answer from the choices below.  Choices: - 25  - anatomy  - animal  - animals  - body  - brain  - british english  - cats  - circulatory system  - communication  - digestion  - dna  - eating  - english  - face  - family  - fish  - head  - hearing  - heart  - house  - human  - human body  - larynx  - medicine  - middle ear  - mouth  - nervous system  - nose  - oesophagus  - organ  - outer ear  - palate  - part  - process  - respiratory system  - species  - stomach  - syntax  - system  - the middle  - throat  - top  - word
A:
head