Answer 1

When four resistors of 16 Ω each are connected in parallel, the effective resistance of the combination can be obtained as: 

`1/R=1/R_1+1/R_2+1/R_3+1/R_4`

or `1/R=1/16+1/16+1/16+1/16` 

or `1/R=4/16` 

or `1/R=1/4` 

or `R=4`Ω 

The effective resistance of combination is 4 Ώ.
When four such combinations are connected in series, the effective resistance becomes:
R = R₁ + R₂+ R₃ + R₄
R = 4 Ώ + 4 Î + 4 Î + 4 Î = 16 Ω