1. What accounts for the differences between the limbs of a human, cat, bat, and whale?

2. Xenobiotics, or toxicants, can alter geneexpression. What does this mean? What effects could ithave on you?

3. What is sigma have to do with DNA OR DNA REPLICATION. I didntunderstand the importance of the SIGMA.

4. Why is it important that capture and detection antibodies aredirected towards different parts of the protein to be detected (theantigen)?