Full marks6/6
4 bits per pixel gives 2^4 = 16 different binary values, so each pixel can be only one of 16 colours. The designers want many shades of green and blue, but most of these cannot be stored exactly and must be approximated or left out. This can cause banding where a smooth change from green to blue should be, so a detailed sprite may look unrealistic. A simple sprite with flat colours could still look acceptable. The designers could choose a palette of 16 colours that includes the most important greens and blues, and design sprites with flat colours instead of gradients. Using more bits per pixel would allow more colours, but the console's hardware may not support this.
Why: Explains 2^4 = 16 colours and the limitation on shades, links this to banding and realism, and gives suitable ways to manage it in the console context. Sustained reasoning, so Level 3.
Some marks4/6
4 bits can store 16 colours. This means the sprite cannot have many colours. It might look bad if it needs lots of shades of green and blue. The designers could use fewer colours in the sprite.
Why: Correctly gives 16 colours and makes a simple link to the sprite's appearance and a way to manage it. There is little development of the effect or the management, so Level 2.
Some marks1/6
4 bits can store 16 colours. This means the sprite will have a low resolution, so it will look blocky. The designers should use a higher resolution to get more shades of green and blue.
Why: One correct point: 4 bits give 16 colours. The answer then confuses colour depth with resolution; increasing resolution would not provide more shades.