Conservation

/ˌkänsərˈvāSHən/

noun

1. the planned management of natural resources to prevent loss, destruction, or waste
Conservation is the preservation of life on Earth, and that, above all else, is worth fighting for.
– Rob Stewart (1961 – )

2. (physics) the principle by which the quantity of something remains constant in a system
Conservation of energy (the First Law of Thermodynamics) is a simple law stating that although energy may change form, it cannot disappear altogether, nor can it be created.
– Wikiversity