Which motor development milestone(s) have most children achieved by 2 years of age?

running

jumping

picking up small objects

all of the above

How does specialization enable countries to trade with one another? a country can make and sell goods affordably and buy goods that it is inefficient at making. a country can make what it chooses and sell its goods to other countries. a country can decide to buy everything it needs from other countries. a country can efficiently make goods that were once difficult to make.