The opening between the right atrium and the right ventricle is guarded by $\_\_\_\_$ .

The WBC count of a person's blood sample is $8000 / \mathrm{cu} \mathrm{mm}$. How many eosinophils and lymphocytes would be in the same blood sample approximately?

Select the incorrect statement with reference to Rh grouping.

A. Erythroblastosis foetalis is a condition observed having foetus with $\mathrm{Rh}^{-\mathrm{ve}}$ blood and mother with $\mathrm{Rh}^{+\mathrm{ve}}$ blood.

B. Rh antigen is observed on RBCs in the majority of human beings.

C. Before blood transfusion, Rh group should also be matched.

D. Rh incompatibility is observed when a pregnant mother is $\mathrm{Rh}^{-\mathrm{ve}}$ and the foetus is $\mathrm{Rh}^{+\mathrm{ve}}$.

E. Erythroblastosis foetalis can be avoided by administering anti-Rh antibodies to the mother immediately after the delivery of the second child.

Choose the answer from the options given below :

What is the name of the blood vessel that carries deoxygenated blood from the body to the heart in a frog?