How is the following passage from a cause and effect essay organized?

The greenhouse gas theory states that, in normal conditions, sunlight warms the earth during the day. Then, at night the earth
cools down. However, over the years, gases such as carbon dioxide have been released into the atmosphere. Now, those gases trap the heat that the earth would have cast off before.

A: By chronological order
B: Point by point
C: Subject by subject
D: By order of importance