In an experiment testing the efficacy of cough syrup Brand X, researchers selected 500 participants for the study, and created a control and a placebo group. For this experiment to be considered controlled, a criterion is that:

A) the groups must contain a large number of participants to ensure statistical significance.
B) no variation exists among the control group.
C) no variation exists among the 500 participants.
D) the variation between the participants is randomly divided into the two groups.
E) the researchers must never know the group in which the participants are included.


D) the variation between the participants is randomly divided into the two groups.

Biology & Microbiology

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Horizontal gene transfer has been thoroughly documented for genes involved in

A) DNA replication and repair. B) virulence and metabolic functions. C) only very few processes. D) translation.

Biology & Microbiology

Crocodiles are living representatives of ____

a. anapsids b. archosaurs c. lepidosaurs d. synapsids e. dinosaurs

Biology & Microbiology

The main difference between facilitated transport and osmosis is that

a. facilitated transports the passive transport of water, while osmosis moves solute particles. b. osmosis is the diffusion of water while, facilitated transport moves solute particles. c. facilitated transport requires energy while osmosis does not. d. osmosis requires a transport protein while facilitated transport does not.

Biology & Microbiology

Industrial melanism is a term 

A. describing the color change induced by living in industrialized areas. B. explaining that the darker moths have higher mutation rates because of industrialization. C. describing the evolutionary process in which initially light-colored organisms become dark as a result of natural selection. D. explaining that the darker moths having higher reproductive success because of their pigmentation. E. describing the widespread implementation of pollution controls.

Biology & Microbiology