Select the correct answer. Over the last 250 million years, the world changed from a single land mass to a number of different continents. One reason for the change is
expanding ocean floors. What causes ocean floors to expand?
A. convergent plates
B. divergent plates
C. slab pull
D. uplift

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.