Across

1. The invention of the __________ engine started the Industrial Age created the demand for fossil fuels.
3. A waste byproduct of cloth and yarn production used in cattle feed.
6. Cattle ______ waste products and turn them into nutritious food and other products we need.
7. First compartment of a cow's stomach that holds a quadrillion microorganisms.
11. Carbon dioxide, methane and nitrous oxide are three main _____________ gases.
14. We can raise cattle in places that are too ___________ for other types of farming.
15. What an animal that has a 4-compartment stomach is called.
16. The United States produces 22% of the world's _____ with less than 10% of the cattle.
17. The United States has _______ cattle today than it did 50 years ago.
18. This country contains the most cattle in the world.
19. The Earth's atmosphere is made up of mostly this element.

Down

2. This greenhouse gas is of interest because it breaks down more quickly than the other GHGs.
4. This common household and school product is made from collagen from cattle.
5. Process used by microbes to digest plant material.
8. What a cow does every 4 minutes.
9. This construction material is made from cattle byproducts.
10. __________ digest plant material for cows and other ruminants.
12. If a cow doesn't burp, she will do this.
13. The third largest contributor to methane emission in the U.S.
16. There are roughly one __________ cattle on the planet today.