Which improves the integrity of an experimental investigation? 1. Keeping as few constants as possible
2. Having several (at least 2-3) independent variables
3. Keeping everything constant except the independent and dependent variable
ILL MARK AS BRAINLIEST

your answer is a. the enthalpy of formation for a pure element in its standard state is always positive.

c is having 4 valence electrons and is bonded to three hydrogens and one sulphur atom, therefore, the number of bond pair is equal to four. as all the valence electrons are used in forming the bonds so, there is no lone pair left on carbon.

s is having 6 valence electrons and is bonded to one other sulfur atom and one carbon atom, therefore, the number of bond pair is equal to 2. as only two valence electrons are used in forming the bonds so, four electrons are left. therefore, two lone pairs are present on s.