Use the Following Information When Answering the Corresponding Question(s)

Multiple Choice

Use the following information when answering the corresponding question(s) .
Lymph hearts are pumping structures that drive lymph through the lymphatic system,returning it to the circulatory system at the large veins entering the heart.Researchers examined rate and strength of pumping of lymph hearts in two species of amphibians,a toad (Bufo marinus) and a frog (Rana catesbiana) .During hemorrhage or dehydration,the volume of blood in the circulatory system falls.A hormone,arginine vasotocin (AVT) ,is released in these situations.The researchers examined the effect of AVT on lymph heart function.They found that AVT increased pressure at the lymph heart but did not affect the rate of lymph heart pumping.They also examined the effect of atrial natriuretic peptide (ANP) ,a hormone that is released when blood volume is higher than normal.(E.A.DeGrauw and S.S.Hillman.2004.General function and endocrine control of the posterior lymph hearts in Bufo marinus and Rana catesbiana.Physiological and Biochemical Zoology 77(4) :594-600. )
-Refer to the paragraph on lymph hearts.If atrial natriuretic peptide (ANP) has an effect on the lymph hearts,what effect would logically be predicted?

A) Lymph heart rate would increase.
B) Lymph heart rate would decrease.
C) Lymph heart pressure would increase.
D) Lymph heart pressure would decrease.