Use the following scenario to answer questions 67-70

Kayla is a nutritionist and is interested in how diet affects growth in children. Using rats as a
model organism, Kayla set up the following experiment to examine the effects of diet on the
growth of baby rats. She chose rats because, like humans, they nurse their young, and share
many of the same genes. She designed an experiment that measured the effect of a sugar water
diet compared to a diet of breast milk on rat growth. She divided a litter of 6 rats into two groups
of three. Group A was fed a diet of sugar water, and Group B was fed breast milk. Each rat was
fed 5 mL of "food" each day. Kayla determined the mass of each rat once a week for 4 weeks.


67. What is the independent variable in this experiment?

68. What is the dependent variable in this experiment?

69. What is the control group in this experiment?

70. What variable(s) were constant in the different groups?