In the "sandwich" ELISA pregnancy test, the antibodies that are fixed in the control zone bind specifically to:

In the sandwich enzyme-linked immunosorbent assay pregnancy test, the antibodies in the control bind to the human chorionic gonadotropin (hCG) in the sample which could either be serum or urine of the patient. The horseradish peroxidase serves as an enzyme label that mediates in the reaction to facilitate this binding process.

Explanation:

In the sandwich enzyme-linked immunosorbent assay pregnancy test, the antibodies in the control bind to the human chorionic gonadotropin (hCG) in the sample which could either be serum or urine of the patient. The horseradish peroxidase serves as an enzyme label that mediates in the reaction to facilitate this binding process.

answer; a muscle cell, another neuron and a of the above