Which statement concerning activator and repressor proteins in eukaryotes is true?
a. activators and repressors are equally common in eukaryotes.
b. activators and repressors are only found in prokaryotes.
c. repressors are more common than activators in eukaryotes.
d. activators are more common than repressors in eukaryotes.

According to the federal regulations, which of the following studies meets the definition of research with human subjects? a researcher conducts a comparison of the comments made in a publicly available blog and the blogger's comments on a similar topic in a weekly magazine. undergraduate students in a field methods class are assigned a research question and asked to interview another classmate, to be followed by a class discussion on interview techniques. a cognitive psychologist enrolls undergraduate students for a computer-based study about the effect of mood on problem-solving behaviors. a researcher sets up a meeting with the superintendent of a large and diverse public school system to get data about the ethnic composition of the school system and the number of students receiving free lunches.