The parts of human excretory system are given below.
In which order does urine pass through these structures?
A (ii) → (iii) → (i) → (iv)
B (i) → (iii) → (iv) → (ii)
C (ii) → (iv) → (i) → (iii)
D (iv) → (iii) → (i) → (ii)
The diagram below shows three ring
magnets, P, Q and R. Identify the poles of P, Q and R.