so they can see , spastic.
It has light and it also produces its own light and thus when it is very dark it could lit up its own light and see clearly.
behavioral
john( the fish produces light ), Mary ( the fish produces light ), ,Toby ( the fish produces light ), may ( the fish produces light ),
Fish live in it
Both are acceptable, depending on context. For example:Fishing bait is useful to fisherman.Fishing bait is useful for catching fish.
it's useful for light and safety.
The light bulb is useful because it lights up places!
Of course it is in its name.
both
light fish live in the artic ocean
The useful energy that comes out of a light bulb is primarily in the form of light and heat. The electrical energy is converted into light energy that illuminates the surroundings and heat energy that warms up the light bulb and its surroundings.
The useful energy in a light bulb is the light that it emits. When electricity flows through the filament of a light bulb, it produces light energy that we can see and use for illumination.