Answer:
Explanation:
Remark
The sun releases both visible and ultraviolet light.
Humans can only see visible light.
I take it what you are trying to do is make this into a compound sentence. To do that, I think either ,but or ; should be used.
,but
The sun releases both visible and ultraviolet light, but humans can only see visible light.
;
The sun releases both visible and ultraviolet light; humans can only see visible light.
Opinion
Usually, I prefer the semi colon, but in this case, it seems to me that the coordinating conjunction works better. Both are correct.
