The diameter of the is so thin that only one red blood cell can get through at a time. 1) Vein

2) Capillary

3) Arteriole

4) Artery

Answer and I will give you brainiliest

Students in biology are studying the macromolecules of life. they used a calorimeter to determine the calories in various types of food. once the lab was completed, the students ate the left over food samples. monica commented that in just 6 or 7 "chews" of the saltine, it was gone; nothing but a sticky paste in her mouth. elaborate on what happened chemically while chewing the saltine. include the macromolecules present.