What is a very small tube that carries blood?

What element is able to combine with itself and hydrogen to form large molecules ?

Photosynthesis uses co2 and cellular respiration produces co2. we call the point when the two processes are in balance--when there is no net production of co2--the compensation point. how might you limit one of the processes in order to achieve a compensation point?

Which of the following is the function of the nociceptors? a. detecting odors in the nose b. detecting painful stimuli c. detecting central body temperature d. detecting touch and pressure