Your best bet is B or D. Most likely B
The answer is 1) gained
Always <span><span>think "into" for "endo" (energy goes in), and "exit" for "exo" (energy is released).</span> </span>
Hope it helps ^-^
Water purification is the process of removing undesirable chemicals, biological contaminants, suspended solids and gases from contaminated water. The goal is to produce water fit for a specific purpose. Most water is disinfected for human consumption (drinking water), but water purification may also be designed for a variety of other purposes, including fulfilling the requirements of medical, pharmacological, chemical and industrial applications. The methods used include physical processes such as filtration, sedimentation, and distillation; biological processes such as slow sand filters or biologically active carbon; chemical processes such as flocculation and chlorination and the use of electromagnetic radiation such as ultra violet light.