Final answer:
To gain practice in analyzing cDNA sequences from a cDNA library, you need to work on b) expression clones. Expression clones contain DNA sequences that can produce the protein encoded by the cDNA sequence, allowing for the study of its function and characteristics.
Step-by-step explanation:
To gain practice in analyzing a cDNA sequence from a cDNA library, you would need to work on expression clones. Expression clones contain DNA sequences that have been inserted into a vector and can be used to produce the protein encoded by the cDNA sequence. By analyzing the expression of the gene product, you can study the function and characteristics of the cDNA sequence.