All of the following are possible sources of error in a scientific investigation except for

1- discovering new variables as the experiment proceeds

2- not controlling all the variables in the experiment

3- adding research resources during an investigation

4- measuring the materials of an experiment incorrectly

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