Metabolic Rate

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Across:

1. The quantity of energy consumed per unit of time. (9,4)
3. A device used to measure metabolic rate. (12)
4. A device used to measure metabolic rate. (11)
6. Type of circulatory system found in vertebrates but not in fish. (6)
7. Tiny channels found in a bird's lungs. (11)
9. Type of circulatory system found in vertebrates. (6)
10. Circulatory system found in reptiles and amphibians. (10)
11. Device used to measure maximum oxygen uptake. (9)
13. Metabolic rate measure the quantity of ______ consumed per unit time. (6)

Down:

2. Waste product of respiration. (6,7)
5. Type of circulatory system found in fish. (6)
8. Tiny air sacs found in lungs. (7)
12. Gas used up in respiration. (6)