In order to maintain homeostasis, the systems of the human body work together to keep a constant internal temperature. Which of the following best describes how the human body responds in a cold environment ? A. The digestive system produces more hormones to warm the body. B. The nervous system signals the muscles of the muscular system to contract and warm the body. C. The circulatory system delivers less carbon dioxide to the muscular system, resulting in stiffening of the muscles. D. The skeletal system produces more blood cells that circulate through the blood vessels, increasing the warmth of the body.

Refer to this portion of a dichotomous key for fish identification to answer the question. 1. (a) has a single dorsal fin ® 5 (b) has a double dorsal fin ® 2 2. (a) one fin is spiny, the other is smooth ® 3 (b) one fin is not spiny or smooth ® 4 5. (a) has small fin on back near tail ® 6 (b) has no fin on back near tail ® 7 6. (a) has barbs near the mouth ® catfish (b) does not have barbs near the mouth ® 10 7. (a) tail is asymmetrical ® 8 (b) tail is symmetrical ® 9 10. (a) scales are small ® trout (b) scales are large ® whitefish what is the next step to complete to identify a fish that has a single dorsal fin, no fin on the back near the tail, and no barbs near the mouth? step 2 step 5 step 7 step 10