The "decision" as to whether a neuron fires or not can be described as MOST similar to:

The "decision" as to whether a neuron fires or not can be described as most similar to: the underdog wins.

Explanation:

There are five different ways, in which we can arrange the photos.

Step-by-step explanation:

There are five  different ways to arrange the photos.

1. 5 photos in each 4 rows.

2. 4 photos in each 5 rows.

3. 2 photos in each 10 rows.

4. 10 photos in each 2 rows.

5. 20 photos in a single row.