Apharmaceutical company is testing a new drug that they claim allows dogs to repel
flea infestation. they give 100 dogs the medication and another 100 dogs a sugar
pill.
which of the following is true of this experiment?
the sample size is too low.
the sugar pill would be a placebo.
the independent variable is the number of fleas on dogs.
the dogs with the placebo would be the experimental group.

Which of the following observation darwin shape his concept of descent with modification? a) species diversity declines farther from the equator. b) fewer species live on islands than on the nearest continents. c) birds live on islands located farther from the mainland than the bird's maximum nonstop flight distance. d) south american temperate plants are more similar to the tropical plants of south america than to the temperate plants of europe. e) earthquakes reshape life by causing mass extinctions.