Which of the following energy sources harnesses the power of waves?
a. hydroelectric
b. hydrokinetic
c. wind
d. geothermal

Which of the following is always a reactant in a combustion reaction? oxygen nitrogen hydrogen carbon

Describe the difference between a. a hypothesis and a theory and b. an observation and an experiment.

Why is the bond angle in a water molecule less than the bond angle of methane? a. the central oxygen atom in water has two lone pairs of electrons, whereas the central carbon atom in methane has no lone pairs. b. the central hydrogen atom in water has one lone pair of electrons, whereas the central carbon atom in methane has two lone pairs. c. the central oxygen atom in water has four lone pairs of electrons, whereas the central carbon atom in methane has only one lone pair. d. the central oxygen atom exerts more repulsive force on surrounding atoms than the central carbon atom in methane does. reset next