The human circulatory system A) helps maintain a constant body temperature.
B) carries cells that help protect the body from disease.
C) helps the body regulate body temperature.
D) all of the above

True or false: (a) the strings of little red dots represent carbohydrates. (b) the model is called a bilayer because there are two main types of molecules present, lipids and proteins. (c) the many black lines represent amino acid tails. (d) this model shows membrane transport. (e) the blue ovals are hydrophobic. (f) the blue ovals represent phospholipid heads.