Both. You can use it as singular or plural.
The answer is squamous cell carcinoma. This is a type of
cancer where in one cause of this for it to occur is due to exposure of the sun
light. They have different types and two categories that fall in such as
melanomas and non melanoma.
It could occur after a forest fire or flood.
The answer is; 24 hours.
Scientists called the full rotation of the earth a day and divided it into 24 hours on the clock. This means from sunrise to next sunrise. They also divided the earth into latitudes that indicate time zones. When one point on earth rotates and return to the same position in space, it has lapsed 24 hours.