This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Microbiology
The egg which of the following parasites consist of polar filaments arising from either end of the ambrophore? 
Select and explain. 
A. Taenia saginata, B. Taenia solium, C. Echinococcus granulosus, D. Hymenolepis nana
D: Hymenolepis nana
Answer: D: Hymenolepis nana 
Explanation: Ans. is 'd' i.e., H. nana . Egg of H. nana - Spherical or oval - Two distinct membrane, (a) outer membrane (b) inner embryophore - Polar filaments emanating from little knobs at either end of embryophore. - Floats in saturated solution of common salt.