If plants are grown for several days in an atmosphere containing 14CO2 in place of 12CO2 one would expect to find
a. very little radioactivity in the growing leaves
b. large amounts of radioactive water released from the stomates
c. a large increase in the 14C in the starch stored in the roots
d. a large decrease in the rate of carbon fixation in the guard cells
Answer: a large increase in 14C in the starch stored in the roots.