Question

(b) has a double dorsal fin ® 2

1. (a) one fin is spiny, the other is smooth ® 3

(b) one fin is not spiny or smooth ® 4

1. (a) has small fin on back near tail ® 6

(b) has no fin on back near tail ® 7

1. (a) has barbs near the mouth ® catfish

(b) does not have barbs near the mouth ® 10

1. (a) tail is asymmetrical ® 8

(b) tail is symmetrical ® 9

1. (a) scales are small ® trout

(b) scales are large ® whitefish

what is the next step to take to identify a fish that has a single dorsal fin and no fin on the back near the tail?
step 5
step 2
step 7
step 6

Explanation:

1. Analyze the fish's characteristics: single dorsal fin (so we didn't take the path of "double dorsal fin" in step (b) of the first part, but the key here is the next step after knowing no fin near tail).
2. The fish has no fin on the back near the tail. Looking at the key, step 5(b) leads to step 7. So after determining no fin near tail (from step 5(b)), the next step is step 7, which checks the tail's symmetry (asymmetrical or symmetrical).
3. Eliminate other options: Step 5 is about the fin near tail (we already used that to get to no fin, so next isn't step 5). Step 2 is about fin types (spiny/smooth) which is for double dorsal fin path. Step 6 is about barbs near mouth, related to step 5(a) path (fin near tail). So only step 7 is correct.

Answer:

step 7