Answer:
the length of each shape will alternate between even numbers and is numbers.
Explanation:
just think !
there are 3 cubes in the basic shape.
now, with every step he adds 1 more cube to the length, and one more cube to the height. that means 2 more cubes.
so, it goes 3, 5, 7, 9, ... cubes
therefore, the first answer is wrong. the shape in every step will always have an uneven (odd) number of boxes. remember, adding an even number to an uneven number will always result in an uneven number. only uneven and uneven or even and even can have even results.
but the length itself - he only adds there one box at a time, will go
2, 3, 4, 5, 6, ...
so, it will alternate between even and uneven numbers.