Biology, 30.10.2019 04:31 billycain9647
Residents of three villages with three different sources of water supply were asked to participate in a survey to identify cholera carriers. becuase several cholera deaths had occurred lately, nearly everyone agreed to be examined. the proportion of residents in each village who were carriers was computed and compared. what kind of study was this? a. cross-sectional study
b. case-control study
c. prospective cohort study
d. retrospective cohort study
e. experimental study
Answers: 2
Biology, 22.06.2019 02:30, ComicSans10
Sally and sue were investigating the topic of friction in science. they used a small car and a ramp as seen in the picture to test what they were learning. they knew that they slipped easily on waxed floors but not on carpet, so they decided to change the material on the surface of the ramp to see what happened. they planned to use glass, carpet, aluminum foil, and sandpaper and run the car down the ramp over each surface. what would be the best research question to guide the girls' experiment? a) does the amount of surface area affect the friction on the moving car? b) will the car travel fastest on the glass surface? c) how does the angle of the ramp affect the speed of the car? d)do rougher surfaces tend to create more friction than smooth surfaces?
Answers: 1
Residents of three villages with three different sources of water supply were asked to participate i...
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