1. a. 7 cubes have 84 edges
b. 7 cubes have 42 edges
c. 7 cubes have 56 edges

2.

a.
b.
(i)
Prism
(i)
(ii)
Prism
(ii)
(iii)
Pyramid
(iii)
(iv)
Prism
(iv)
(v)
Pyramid
(v)
(vi)
Prism
(vi)

3.

a.  b.  c. 

4. a. AE or DG or BF or CH

b. A, B, C, D, E, F, G or H

c. ABCD or EFHG

d. AC or BD or EH or FG