Why do we include femtometer on this scale if we cannot cannot know for certain the size of objects when they are this small?

At the complete end of cellular respiration, how many molecules of atp are produced?               a.  15    b.  26    c.  38    d.  34 

What is a coast of using technology to transport water? a. cities can be built in otherwise uninhabitable areas. b. crops can be irrigated and grown in new areas. c. floods can be averted in flood-prone areas. d. freshwater supplies can be depleted in an area.

Where is most of the fresh water on earth found a in the ocean b in glaciers and in ice caps c in rivers d in the soil