To see if breast-feeding influences the incidence of the disease rickets, researchers study rates of breast-feeding of infants with and without rickets. This is an example of
A. experimental research.
B. observational research.
C. epidemiological research.
D. double-blind placebo-controlled research.
Question 2
It is very important in a double-blind, placebo-controlled study that all of the factors that could influence the study results are
A. completely different for the groups of subjects.
B. equal and opposite for the groups of subjects.
C. kept to a minimum.
D. kept the same for the groups of subjects.
A marine food web in action: feeding baleen whales and birds.
Groundhog feeding
Hirschsprung Disease
Teenage Pregnancy Rates in Developed Countries
The study of how traits such as flower color are passed from generation to generation provided the m
Demographic transition model for changes in population growth rates and sizes, correlated with long-