Sandy is three years old and has 20/40 vision. what does this mean?

It means she has 10/20 vision
Which means she needs glasses

It means she can only see at 20 feet while someone with 20/20 vision would be able to see at 40 feet

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.