GAAGCGATCAGTTACG
What is the RNA strand

Ribonucleic acid

Explanation:

Ribonucleic acid is a polymeric molecule essential in various biological roles in coding, decoding, regulation and expression of genes. RNA and DNA are nucleic acids. Along with lipids, proteins, and carbohydrates, nucleic acids constitute one of the four major macromolecules essential for all known forms of life.

hormones in blood stream

image: dtc.ucsf.edu

endocrine glands secrete hormones into the blood stream near them; the hormones then travel in our bloodstream until it reaches its destination, called a target cell, in distance parts of the body. in the target tissue, hormones lock onto the target’s plasma membrane, called the receptor site.

i believe it is "they are not used up by reactions" as the answer to your question, text me back if this is correct because i just learned this.