Whenever julie played with toy vehicles or blocks her mother would be very disapproving. whenever she played with dolls and domestic toys her mother would smile and praise her. as julie grew up, she played less and less with "boys" toys and more and more with dolls, dollhouses, and domestic accessories. this description of gender-role development exemplifies theory?

The correct answer is social learning theory.
According to this theory, proposed by Albert Bandura, our behavior is learned from our environment and observation. So, whenever Julie played with 'boys' toys, her mother would show signs of disapproval, and thus Julie learned that it is something wrong to do. When she played with 'girls' toys, her mother would show her approval, and thus Julie learned that this is something she should be doing. 

The  ancient egyptians  who  built the pyramids  may have been  able  to move massive stone blocks across the desert by wetting the sand in front of a contraption  built  to pull the heavy objects