A situation where several negative factors interact as cause and effect, leading to a continuous decline or worsening of conditions; a downward spiral.

The circulation of blood through the smallest vessels, such as the capillaries.

A sports tournament where contestants take turns playing against every other contestant in their group, with the winner determined by the total points or wins accumulated.

The movement of blood through the body's cardiovascular system; also written as [[血液循环|血液循環|xue4 ye4 xun2 huan2]]

the organ system in humans and vertebrate animals, consisting of the heart, blood vessels, and lymph, that transports nutrients and oxygen throughout the body

The general circulation of blood through the body, moving from the left ventricle through the arteries to all parts of the body and returning to the right atrium through the veins; also called [[体循环|體循環|ti3 xun2 huan2]].

To move or run in circles; to go round and round in a recurring cycle.

The continuous movement of water between the oceans, atmosphere, and land, involving processes like evaporation and precipitation; also called [[水文循环|水文循环|shui3 wen2 xun2 huan2]]

The part of the circulatory system that carries oxygenated blood from the left ventricle through the body to provide nutrients and remove waste, returning it to the right atrium; also called [[大循环|大循環|da4 xun2 huan2]].

The path of blood flow from the right ventricle of the heart to the lungs and back to the left atrium; also known as [[小循环|小循環|xiao3 xun2 huan2]].

recurring in a cycle or circle; circulatory; recursive

The process through which carbon is exchanged between the atmosphere, oceans, soil, and living organisms; primarily involving the conversion of [[二氧化碳|二氧化碳|er4 yang3 hua4 tan4]] into organic compounds by plants and its return to the air through respiration and decomposition.

a logical fallacy in which the reasoner begins with what they are trying to end with; begging the question

The path of blood from the heart to the lungs and back to the heart; also called [[肺循环|肺循環|fei4 xun2 huan2]]

A decimal fraction in which a figure or group of figures is repeated indefinitely; includes both pure repeating decimals (repeating from the first decimal place) and mixed repeating decimals.

virtuous cycle; positive feedback loop; self-sustained growth or improvement

The movement of blood through the heart and blood vessels to transport nutrients and oxygen to cells and remove waste products.

a specialized microbody or organelle in plants and fungi that contains enzymes for the glyoxylate cycle

The Rankine cycle, used in engineering to model the process by which steam-operated heat engines generate power.

to recycle; to recirculate; recycling; recirculation

the circulation of blood in the blood vessels of the heart muscle

a sports tournament format where each contestant meets all other contestants once

A competition format where each participant or team plays every other participant exactly once

The law of heaven where good is rewarded and evil is punished in a continuous cycle; justice will be served in the end.

The natural law of cause and effect or cosmic justice; the idea that good and evil actions will eventually meet with their deserved reward or punishment.

to recycle; to use in a cycle, as in reusing materials or objects that have already been used

to reuse materials or products through a circular process

A model of economic development based on the continuous reuse and recycling of materials; specifically aimed at resource efficiency and environmental sustainability.

The recurring section of a rational number written as a decimal.

The natural rise and fall of economic growth over time, covering phases from expansion and peak to recession and trough; boom and bust cycle

citric acid cycle; also known as the Krebs cycle or the tricarboxylic acid cycle

infinite loop; endless loop

A decimal that contains both a non-repeating part and a repeating part following the decimal point.

The series of stages that fuel passes through from production or extraction to consumption or disposal