Airmax PondSeries Pond Aeration System, PS10, 1 Diffuser, 115V, (1) 100 ft. Roll of 3/8 in. Airline, Aerates Up to 1 Acre

1 (one, unit, unity) is a number, numeral, and glyph. It is the first and smallest positive integer of the infinite sequence of natural numbers. This fundamental property has led to its unique uses in other fields, ranging from science to sports, where it commonly denotes the first, leading, or top thing in a group. 1 is the unit of counting or measurement, a determiner for singular nouns, and a gender-neutral pronoun. Historically, the representation of 1 evolved from ancient Sumerian and Babylonian symbols to the modern Arabic numeral.

In mathematics, 1 is the multiplicative identity, meaning that any number multiplied by 1 equals the same number. 1 is by convention not considered a prime number. In digital technology, 1 represents the "on" state in binary code, the foundation of computing. Philosophically, 1 symbolizes the ultimate reality or source of existence in various traditions.

100 or one hundred (Roman numeral: C) is the natural number following 99 and preceding 101.

3 (three) is a number, numeral and digit. It is the natural number following 2 and preceding 4, and is the smallest odd prime number and the only prime preceding a square number. It has religious and cultural significance in many societies.

The acre ( AY-kər) is a unit of land area used in the British imperial and the United States customary systems. It is traditionally defined as the area of one chain by one furlong (66 by 660 feet), which is exactly equal to 10 square chains, 1⁄640 of a square mile, 4,840 square yards, or 43,560 square feet, and approximately 4,047 m², or about 40% of a hectare. Based upon the international yard and pound agreement of 1959, an acre may be declared as exactly 4,046.8564224 square metres. The acre is sometimes abbreviated ac but is usually spelled out as the word "acre".

Traditionally, in the Middle Ages, an acre was conceived of as the area of land that could be ploughed by one man using a team of eight oxen in one day.

The acre is still a statutory measure in the United States. Both the international acre and the US survey acre are in use, but they differ by only four parts per million (see below). The most common use of the acre is to measure tracts of land.

The acre is used in many established and former Commonwealth of Nations countries by custom. In a few, it continues as a statute measure, although not since 2010 in the UK, and not for decades in Australia, New Zealand, and South Africa. In many places where it is not a statute measure, it is still lawful to "use for trade" if given as supplementary information and is not used for land registration.

Aeration (also called aerification or aeriation) is the process by which air is circulated through, mixed with or dissolved in a liquid or other substances that act as a fluid (such as soil). Aeration processes create additional surface area in the mixture, allowing greater chemical or suspension reactions.

An airline is a company that provides air transport services for traveling passengers or freight. Airlines use aircraft to supply these services and may form partnerships or alliances with other airlines for codeshare agreements, in which they both offer and operate the same flight. Generally, airline companies are recognized with an air operating certificate or license issued by a governmental aviation body. Airlines may be scheduled or charter operators.

The first airline was the German airship company DELAG, founded on November 16, 1909. The four oldest non-airship airlines that still exist are the Netherlands' KLM (1919), Colombia's Avianca (1919), Australia's Qantas (1920) and the Russian Aeroflot (1923).

Airline ownership has seen a shift from mostly personal ownership until the 1930s to government-ownership of major airlines from the 1940s to 1980s and back to large-scale privatization following the mid-1980s. Since the 1980s, there has been a trend of major airline mergers and the formation of airline alliances. The largest alliances are Star Alliance, SkyTeam and Oneworld. Airline alliances coordinate their passenger service programs (such as lounges and frequent-flyer programs), offer special interline tickets and often engage in extensive codesharing (sometimes systemwide).

Airmax or Air Max may refer to:

• Nike Air Max, a line of shoes first released by Nike, Inc.
• AirMax, a proprietary wireless protocol and wireless product brand developed by Ubiquiti Networks
• Air Max Africa, an airline based in Libreville, Gabon
• AirMax SeaMax, a Brazilian single-engine, amphibious light sport aircraft

A pond is a small, still, land-based body of water formed by pooling inside a depression, either naturally or artificially. A pond is smaller than a lake and there are no official criteria distinguishing the two, although defining a pond to be less than 5 hectares (12 acres) in area, less than 5 metres (16 ft) in depth and with less than 30% with emergent vegetation helps in distinguishing the ecology of ponds from those of lakes and wetlands.^: 460 Ponds can be created by a wide variety of natural processes (e.g. on floodplains as cutoff river channels, by glacial processes, by peatland formation, in coastal dune systems, by beavers), or they can simply be isolated depressions (such as a kettle hole, vernal pool, prairie pothole, or simply natural undulations in undrained land) filled by runoff, groundwater, or precipitation, or all three of these. They can be further divided into four zones: vegetation zone, open water, bottom mud and surface film.^{: 160–163} The size and depth of ponds often varies greatly with the time of year; many ponds are produced by spring flooding from rivers. Ponds are usually freshwater but may be brackish in nature. Saltwater pools, with a direct connection to the sea to maintain full salinity, may sometimes be called 'ponds' but these are normally regarded as part of the marine environment. They do not support fresh or brackish water-based organisms, and are rather tidal pools or lagoons.

Ponds are typically shallow water bodies with varying abundances of aquatic plants and animals. Depth, seasonal water level variations, nutrient fluxes, amount of light reaching the ponds, the shape, the presence of visiting large mammals, the composition of any fish communities and salinity can all affect the types of plant and animal communities present. Food webs are based both on free-floating algae and upon aquatic plants. There is usually a diverse array of aquatic life, with a few examples including algae, snails, fish, beetles, water bugs, frogs, turtles, otters, and muskrats. Top predators may include large fish, herons, or alligators. Since fish are a major predator upon amphibian larvae, ponds that dry up each year, thereby killing resident fish, provide important refugia for amphibian breeding. Ponds that dry up completely each year are often known as vernal pools. Some ponds are produced by animal activity, including alligator holes and beaver ponds, and these add important diversity to landscapes.

Ponds are frequently man made or expanded beyond their original depths and bounds by anthropogenic causes. Apart from their role as highly biodiverse, fundamentally natural, freshwater ecosystems ponds have had, and still have, many uses, including providing water for agriculture, livestock and communities, aiding in habitat restoration, serving as breeding grounds for local and migrating species, decorative components of landscape architecture, flood control basins, general urbanization, interception basins for pollutants and sources and sinks of greenhouse gases.

A system is a group of interacting or interrelated elements that act according to a set of rules to form a unified whole. A system, surrounded and influenced by its environment, is described by its boundaries, structure and purpose and is expressed in its functioning. Systems are the subjects of study of systems theory and other systems sciences.

Systems have several common properties and characteristics, including structure, function(s), behavior and interconnectivity.