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
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

according to this dichotomous key, any catfish must have
a double dorsal fin, a small fin on the back near the tail, and barbs near the mouth.
a single dorsal fin, no small fin on the back near the tail, and barbs near the mouth.
a double dorsal fin, a small fin on the back near the tail, and no barbs near the mouth.
a single dorsal fin, a small fin on the back near the tail, and barbs near the mouth.

Mike was adopted, and his biological family history is unknown. although he is healthy, he would like some understanding of his genetic makeup, including potential health risks and genes that he could pass on to his children. mike has heard about commercial laboratories that can compare segments of your dna to those of people with common hereditary diseases in order to give you some idea of how susceptible you are to the diseases. the results of these types of tests are highly inconclusive. if mike's dna showed that he shares similarities in a segment of dna with people who have a given disease, his chances of developing that disease or passing it on to his children may be slightly elevated, but they are not 100 percent. these tests can cost more than $2,500 and are not covered by many insurance companies. do you think that mike should undergo the genetic tests? explain your answer. what are the potential pros and cons of having such tests done? describe how the availability of these genetic tests might affect the frequency of genetic diseases in individuals and populations.

How did the research presented in the article affect scientists' understanding of the evolution of eukaryotes

What is a gene ? a) a section of a protein that codes for dna. b) the alternate version of a trait. c) the visible trait in the f1 generation. d) a section of dna that codes for a specific trait .