Roots of a plant typically grow downward, Walt shoots grow upward. This is most likely the result of differences in the-

A) concentrations of auxins in response to gravity

B) speed of fluid transport in response to temperature

C) percentage of open stomata in response to humidity

D) Active transport of nutrients in response to light

Aresearcher designed an investigation to test what effect eating different types of food would have on blood insulin levels. she selected 10 male subjects who were all 25 years of age and in good health. the experiment took place over 3 days. at 8: 00 a. m. on each day, the subjects ate a meal consisting of only 1 type of food. they had their blood insulin levels measured after consuming the meal. on day 1 they ate a high fat diet, on day 2 they ate a high protein diet, and on day 3 they ate a high sugar diel what is the independent variable in this experiment? a the age of the subjects b the blood insulin level c the type of food consumed d the time of day the meal was consumed