1 hormones
2 external stimuli
Answer:
Explanation:
Look I would help but I'm not learning that stuff yet in Middle School.
<span>Simply because cells need both these types of molecules for proper function.</span>
<span>Blood is a liquid and has cellular parts. The liquid contains substances such as proteins and lipids. The cellular constituents are erythrocytes (red blood cells), leukocytes and platelets.</span>
