increasing the depth of tank

decreasing the depth of tank

increasing the surface area of tank

decreasing the surface area of tank

less and more

less and less

more and less

more and more

(i) and (ii)

(i)and(iv)

(ii) and (iii)

(ii) and (iv)

2 to 4

4 to 6

6 to 8

8 to 10

1 to 2 minutes

30 to 45 minutes

2 to 6 hours

2 to 6 days