Earth Day Crossword

What month is Earth Day celebrated?
Which layer absorbs most of the ultraviolet radiation reaching the Earth from the sun?
What is a word commonly found in a saying to mean "use less of?"
Branch of biology that deals with the relations of organisms to one another and to their physical surroundings.
A process that happens in the leaves of plants which is converted into food and oxygen.
The saying goes, "Reduce, reuse, _______." What is the blank?
A gas that contributes to the greenhouse effect.
Plants absorb this in photosynthesis.
Very common type of trash that hurts sea animals.
A natural fuel such as coal or gas, formed in the geological past from the remains of living organisms.
A gradual increase in the overall temperature of the Earth's atmosphere.
What do trees give off?
What part of the tree makes paper?
What vitamin does the sun give off?
What forest produces the most oxygen?