Dna isolated from water samples collected in six different sites was prepared and anaylized by gel eletrophoresis for the presense of carp. the resulting gel is shown. lane 1 through 6 contain the dna from each site. lane 7 and 8 represent the negative and positive controls. based on the bending patterns, how many sites tested positive for carp?

Which statements best describe the differences or similarities between a comparative investigation and an experimental investigation? check all that apply. experimental investigations are best for showing cause-and-effect relationships, while comparative investigations do not necessarily show this type of relationship. comparative investigations are often impractical and unrealistic, while experimental investigations are the most practical and realistic kinds of investigations. comparative investigations allow for the use of a wide range of variables but do not have a control group, while experimental investigations involve variables that can be controlled. both experimental investigations and comparative investigations are designed to answer scientific questions. both experimental investigations and comparative investigations focus on making observations rather than collecting new data.