Makers of videos developed for infants and toddlers have claimed that the videos promote brain development. however, a study by zimmerman and colleagues showed that viewing baby media was with vocabulary growth in infants.

I believe the answer is: negatively correlated
According to the study conducted by Zimmerman, the more time infants spent in watching the media, the less time they would have in observing and being involved with actual interaction with human beings, which eventually led the stunt in vocabulary development.

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

The correct answer is a. when they started making tools that will them in cultivating lands, they could raise crops and that made them attached to one place for a longer period of time. after that, they started domesticating animals and building their own permanent settlements that resemble the ones we have today.