What was the purpose of the vinegar in the third trial? a. test the effect of raising pH on enzyme action
b. served no purpose
c. serve as a control
d. test the effect of lowering pH on enzyme action

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.