Why was one group given a sugar tablet as a placebo

Which taxon group is more specific, in regards to organisms that are in that group? mammalia animalia

Ascientist wants to determine the effect of a new type of gasoline. he fillsone car with normal gasoline and another identical car with the new gasoline.which is the control group? a. the new type of gasolineb. the car with the normal gasolinec. the car with the new gasolinethe amount of gasoline usedd. the amount of gasoline used

Examine the air pressure map. which type of line is shown on the map?