quitzlet A researcher uses a video camera to record children as they play on a school playground. The researcher plans to carefully watch the videotape to count the children's helping behaviors. This researcher is conducting a: case study systematic observation. standardized test. multisource study.

Click on  the link  to view information gathered by the organization keep america beautiful. read "the costs of american littering" to find three negative effects of litter in local communities.  based on your research, what are the negative effects of litter in local communities? check all that apply. litter cleanup is very expensive. litter has decreased since 1969.litter is a constant community problem. litter causes property in the community to be less valuable. litter contaminates water and has other environmental consequences.