Bone in the context of "Connective tissue"

A tool is an object that can extend an individual's ability to modify features of the surrounding environment or help them accomplish a particular task, and proto-typically refers to solid hand-operated non-biological objects with a single broad purpose that lack multiple functions, unlike machines or computers. Although human beings are proportionally most active in using and making tools in the animal kingdom, as use of stone tools dates back hundreds of millennia, and also in using tools to make other tools, many animals have demonstrated tool use in both instances.

Early human tools, made of such materials as stone, bone, and wood, were used for the preparation of food, hunting, the manufacture of weapons, and the working of materials to produce clothing and useful artifacts and crafts such as pottery, along with the construction of housing, businesses, infrastructure, and transportation. The development of metalworking made additional types of tools possible. Harnessing energy sources, such as animal power, wind, or steam, allowed increasingly complex tools to produce an even larger range of items, with the Industrial Revolution marking an inflection point in the use of tools. The introduction of widespread automation in the 19th and 20th centuries allowed tools to operate with minimal human supervision, further increasing the productivity of human labor.

The human body is the entire structure of a human being. It is composed of many different types of cells that together create tissues and subsequently organs and then organ systems.

The external human body consists of a head, hair, neck, torso (which includes the thorax and abdomen), genitals, arms, hands, legs, and feet. The internal human body includes organs, teeth, bones, muscle, tendons, ligaments, blood vessels and blood, lymphatic vessels and lymph.

A fossil (from Classical Latin fossilis, lit. 'obtained by digging') is any preserved remains, impression, or trace of any once-living thing from a past geological age. Examples include bones, shells, exoskeletons, stone imprints of animals or microbes, objects preserved in amber, hair, petrified wood and DNA remnants. The totality of fossils is known as the fossil record. Though the fossil record is incomplete, numerous studies have demonstrated that there is enough information available to give a good understanding of the pattern of diversification of life on Earth. In addition, the record can predict and fill gaps such as the discovery of Tiktaalik in the arctic of Canada.

Paleontology includes the study of fossils: their age, method of formation, and evolutionary significance. Specimens are sometimes considered to be fossils if they are over 10,000 years old. The oldest fossils are around 3.48 billion years to 4.1 billion years old. The observation in the 19th century that certain fossils were associated with certain rock strata led to the recognition of a geological timescale and the relative ages of different fossils. The development of radiometric dating techniques in the early 20th century allowed scientists to quantitatively measure the absolute ages of rocks and the fossils they host.

The prehistory of Mesopotamia is the period between the Paleolithic and the emergence of writing in the area of the Fertile Crescent around the Tigris and Euphrates rivers, as well as surrounding areas such as the Zagros foothills, southeastern Anatolia, and northwestern Syria.

In general, Paleolithic Mesopotamia is poorly documented, with the situation worsening in southern Mesopotamia for periods prior to the 4th millennium BC. Geological conditions meant that most of the remains were buried under a thick layer of alluvium or submerged beneath the waters of the Persian Gulf. The Middle Paleolithic witnessed the emergence of a population of hunter-gatherers who lived in the caves of the Zagros and, seasonally, in numerous open-air sites. They were producers of a lithic industry of the Mousterian type, and their funerary remains, found in the cave of Shanidar, indicate the existence of solidarity and the practice of healing between the members of a group. During the Upper Paleolithic, the Zagros was probably occupied by modern man. The Shanidar cave contains only tools made of bone or antler, typical of a local Aurignacian called "Baradostian" by specialists.

Antlers are extensions of an animal's skull found in members of the Cervidae (deer) family. Antlers are a single structure composed of bone, cartilage, fibrous tissue, skin, nerves, and blood vessels. They are generally found only on males, with the exception of reindeer/caribou. Antlers are shed and regrown each year and function primarily as objects of sexual attraction and as weapons.

A burn is an injury to skin, or other tissues, caused by heat, electricity, chemicals, friction, or ionizing radiation (such as sunburn, caused by ultraviolet radiation). Most burns are due to heat from hot fluids (called scalding), solids, or fire. Burns occur mainly in the home or the workplace. In the home, risks are associated with domestic kitchens, including stoves, flames, and hot liquids. In the workplace, risks are associated with fire and chemical and electric burns. Alcoholism and smoking are other risk factors. Burns can also occur as a result of self-harm or violence between people (assault).

Burns that affect only the superficial skin layers are known as superficial or first-degree burns. They appear red without blisters, and pain typically lasts around three days. When the injury extends into some of the underlying skin layer, it is a partial-thickness or second-degree burn. Blisters are frequently present and they are often very painful. Healing can require up to eight weeks and scarring may occur. In a full-thickness or third-degree burn, the injury extends to all layers of the skin. Often there is no pain and the burnt area is stiff. Healing typically does not occur on its own. A fourth-degree burn additionally involves injury to deeper tissues, such as muscle, tendons, or bone. The burn is often black and frequently leads to loss of the burned part.

Hunting is the human practice of seeking, pursuing, capturing, and killing wildlife or feral animals. The most common reasons for humans to hunt are to obtain the animal's body for meat and useful animal products (fur/hide, bone/tusks, horn/antler, etc.), for recreation/taxidermy (see trophy hunting), although it may also be done for resourceful reasons such as removing predators dangerous to humans or domestic animals (e.g. wolf hunting), to eliminate pests and nuisance animals that damage crops/livestock/poultry or spread diseases (see varminting), for trade/tourism (see safari), or for ecological conservation against overpopulation and invasive species (commonly called a cull).

Recreationally hunted species are generally referred to as the game, and are usually mammals and birds. A person participating in a hunt is a hunter or (less commonly) huntsman; a natural area used for hunting is called a game reserve; and an experienced hunter who helps organise a hunt and/or manage the game reserve is also known as a gamekeeper.

A spear is a polearm consisting of a shaft, usually of wood, with a pointed head. The head may be simply the sharpened end of the shaft itself, as is the case with fire hardened spears, or it may be made of a more durable material fastened to the shaft, such as bone, flint, obsidian, copper, bronze, iron, or steel. The most common design for hunting and/or warfare, since modern times has incorporated a metal spearhead shaped like a triangle, diamond, or leaf. The heads of fishing spears usually feature multiple sharp points, with or without barbs.

Spears can be divided into two broad categories: those designed for thrusting as a melee weapon (including weapons such as lances and pikes) and those designed for throwing as a ranged weapon (usually referred to as javelins).

The shoulder girdle or pectoral girdle is the set of bones in the appendicular skeleton which connects to the arm on each side. In humans, it consists of the clavicle and scapula; in those species with three bones in the shoulder, it consists of the clavicle, scapula, and coracoid. Some mammalian species (such as the dog and the horse) have only the scapula.

The pectoral girdles are to the upper limbs as the pelvic girdle is to the lower limbs; the girdles are the part of the appendicular skeleton that anchor the appendages to the axial skeleton.

A limb (from Old English lim, meaning "body part") is a jointed, muscled appendage of a tetrapod vertebrate animal used for weight-bearing, terrestrial locomotion and physical interaction with other objects. The distalmost portion of a limb is known as its extremity. The limbs' bony endoskeleton, known as the appendicular skeleton, is homologous among all tetrapods, who use their limbs for walking, running and jumping, swimming, climbing, grasping, touching and striking.

All tetrapods have four limbs that are organized into two bilaterally symmetrical pairs, with one pair at each end of the torso, which phylogenetically correspond to the four paired fins (pectoral and pelvic fins) of their fish (sarcopterygian) ancestors. The cranial pair (i.e. closer to the head) of limbs are known as the forelimbs or front legs, and the caudal pair (i.e. closer to the tail or coccyx) are the hindlimbs or back legs. In animals with a more erect bipedal posture (mainly hominid primates, particularly humans), the forelimbs and hindlimbs are often called upper and lower limbs, respectively. The fore-/upper limbs are connected to the thoracic cage via the pectoral/shoulder girdles, and the hind-/lower limbs are connected to the pelvis via the hip joints. Many animals, especially the arboreal species, have prehensile forelimbs adapted for grasping and climbing, while some (mostly primates) can also use hindlimbs for grasping. Some animals (birds and bats) have expanded forelimbs (and sometimes hindlimbs as well) with specialized feathers or membranes to achieve lift and fly. Aquatic and semiaquatic tetrapods usually have limb features (such as webbings) adapted to better provide propulsion in water, while marine mammals and sea turtles have convergently evolved flattened, paddle-like limbs known as flippers.