Any condition that can change and that might affect the outcome of the experiment is called a(n)

Small metal disks are pasted onto Miranda's scalp and they are connected by wire to a machine that translates the electrical energy from her brain into wavy lines on a moving piece of paper

From this description, it is evident that Miranda's brain is being studied through the use of __________ a) a CT scan. b) functional magnetic resonance imaging. c) a microelectrode. d) an electroencephalogram.

Hormones are__________

a) the female gonads. b) chemicals released into the bloodstream by the endocrine glands. c) chemicals found in the synaptic vesicles, which when released have an effect on the next cell. d) the male gonads