What is the first step in the creation of a theory?
a. a scientist comes up with an explanation.
b. evidence is found to support an existing explanation.
c. nearly all scientists agree that an explanation is correct.
d. new evidence causes adjustments to an existing explanation.

Your answer would be: A. because scientists use what they have to create a theory, a theory is pretty much an educated guess is what a teacher would say, the theory would need to have evidence in order for it to be an educated guess. The scientist would have to come up with an explanation in order for the theory to work, or be an educated guess.

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.

not sure if this is what you'r looking for eubacteria and archaebacteria