Low-emitting materials are those that have minimal or no emissions of volatile organic compounds (VOCs) and other harmful pollutants that can affect indoor air quality (IAQ)1. Specifying and installing low-emitting materials at the source can help prevent the negative effects of indoor pollutants by reducing the exposure of occupants and workers to these substances2. Some examples of low-emitting materials are paints, coatings, adhesives, sealants, flooring, furniture, and insulation that meet the criteria of third-party certification programs such as Green Seal, Greenguard, or SCS3.

Potable water is water that is suitable for drinking. Potable water meets or exceeds the Environmental Protection Agency's (EPA) drinking water quality standards and is free of contaminants that are harmful to human health. The other options are not suitable for drinking. Graywater is wastewater from sinks, showers, and laundry that can be reused for non-potable purposes such as toilet flushing and irrigation. Greenwater is rainwater that is collected and stored for non-potable uses. Stormwater is runoff from precipitation that can carry pollutants and sediments into waterways. Reference: LEED Green Associate Candidate Handbook, page 26; USGBC, [Water Efficiency], page 2.

According to a study completed by the Heschong Mahone Group, providing increased daylighting in schools can improve student test scores by 7%-18%. Daylighting is the practice of placing windows, skylights, other openings, and reflective surfaces so that sunlight (direct or indirect) can provide effective internal lighting. Particular attention is given to daylighting while designing a building when the aim is to maximize visual comfort or to reduce energy use. Reference: LEED Green Associate Candidate Handbook, U.S. Green Building Council resources

Explanation
According to the LEED v4 Glossary of Terms1, a site that has been graded is commonly defined as previously developed, which means "land that has been altered by paving, construction, and/or land use that would typically have required regulatory permitting to have been initiated (alterations may exist now or in the past)"1. A greenfield is "a site not previously developed or graded that could support open space, habitat, or agriculture"1. A brownfield is "a property, the expansion, redevelopment, or reuse of which may be complicated by the presence or potential presence of a hazardous substance, pollutant, or contaminant"1. A previously undeveloped site is "a site that has never been built on or graded for development"2.