Which immunoglobulin class has a dimeric structure with a secretory component? igm iga ige igg?

The answer is IgA. 
IgA is the immunoglobulin that consists of a dimer or a tetramer, a J-chain polypeptide, and a polypeptide chain called the secretory component. IgA is the principal antibody class in the secretions that bathe the mucosal surfaces, acts as an important first line of defense. It is also an important serum immunoglobulin, mediates a variety of protective functions through interaction with specific receptors and immune mediators.

A- a reduction in biodiversity

1) clean up you lab area2) dispose of the chemicals as instructed by your teacher3) put everything back where it belongs unless your teacher tells you otherwise4) dispose of gloves5) wash hands with soap and water