What is the main purpose of the nervous system in the human body?
a-releasing hormones to regulate body functions
b-circulating oxygen throughout the body
c-relaying messages between the body and brain
d-protecting the body from foreign invaders

Astudent poured a solution of bromothymol blue indicator into three test tubes. then he placed an aquatic plant in two of the test tubes, as shown below. he placed a stopper on each test tube and placed them all in the dark for 24 hours. bromothymol blue turns from blue to yellow in the presence of co2