Question

Frogs differ from humans in possessing
A. Nucleated red blood cells
B. A thyroid as well as parathyroid
C. Paired cerebral hemispheres
D. A hepatic portal system

Answer 1

Hint: Frog belong to class amphibians and humans belong to mammals even there is divergence in the classification, appearance, organs, frogs genome is 90% similar to that of humans and can synthesise homologous proteins as of humans. Due to this reason frogs are used as model organisms for humans in research.

Complete Answer:
- Frogs consist of both thyroid and parathyroid gland where secretion of thyroid hormone is necessary for metamorphosis in frogs which is an essential step in its development and these glands are also present in humans for secretion of thyroid hormone.
- Nervous system in frog is not as complex as humans but they have forebrain which consist of a pair of olfactory lobbed, diencephalon and a pair of cerebral hemispheres which is also seen in human beings but further structural arrangement and complexity of nervous system parts are different in frog compared to humans and vice versa.
- Hepatic portal system is a small arrangement of blue vessels which carry blood from the alimentary canal and glands attached to the alimentary canal to the liver which is responsible for various functions, this complex arrangement is seen in both frogs and humans.
- Red blood corpuscles in humans consist of nucleus in its early stages during hematopoiesis later nucleus is thrown out of the cell in order to increase the carrying capacity of oxygen and thus becomes dumbbell shaped whereas RBC of frog consist of nucleus after development.

So the correct answer is option A.

Note: Removal of nucleus from red blood cells of humans is to make space for the accumulation of more hemoglobin further increasing the carrying capacity of oxygen.