Short-spined sea urchin fossils were found directly above long-spined sea urchin fossils in a layer of rock. What do the differences between the two sets of sea urchin fossils suggest about them? The longer spines developed as the shorter-spined sea urchins grew older.
The longer-spined sea urchins existed before the shorter-spined sea urchins.
The shorter-spined sea urchins stretched their spines to ward off predators.
The shorter spines did not protect the sea urchins well enough and they died off.

Enzymes are proteins that speed up reactions by providing an additional energy source supplying additional molecules for the reaction removing inhibitors that slow down reactions lowering the amount of energy required

Molecular models of two different substances are shown below. in the molecule on the left, the oxygen atom pulls on electrons more strongly than the hydrogen atoms. in the molecule on the right, the two oxygen atoms pull on the shared electrons with the same strength. water molecule, h,o oxygen molecule, oz when the two substances are put in the same container, they do not attract each other. why does this happen? a. they both contain oxygen. b. one is polar and one is nonpolar. c . they are both polar. d. they contain different elements.

In which squares should the phrase "green pods" appear a) a and d b) b and e c)a,c, and d d)a,b,c,d and e