Assertion [A]: Nematodes are pseudocoelomates.
Reason [R]: Perivisceral space is filled with parenchyma derived from mesoderm.
What changes are observed in the uterus:
(i) Subsequent to the implantation of the zygote and
(ii) If an egg does not get fertilized?
Name the part performing the following functions in the human female reproductive system:
(i) Production of eggs
(ii) Site of fertilization
(iii) Site of implantation
(iv) Entry of the sperms
Why are testes in human males located outside the abdominal cavity in scrotum?
Select the option having correct matching of the organism given in Column I with the mode of reproduction in Column II: Column I {0.2cm} 
Two concentric thin circular rings of radii 50 cm and 40 cm each, carry a current of 3.5 A in opposite directions. If the two rings are coplanar, the net magnetic field due to the two rings at their centre is: