How did china's early civilization differ from other river valley civilizations?

select all correct answers.

china's civilization did not die out but continues today.

other civilizations were ruled by a single leader.

the people of ancient china relied on trade to acquire things they needed.

people in ancient china were cut off from others by geographic features.

the people in china worshipped only one god.

im not sure its either a leader of a group of congresspeople or a person from a congressmans district

sorry im not sure

the perimeter of a triangle is 69 cm. side a is 5 cm shorter than side b. side c is twice as long as side a. find the length of each side. i need to know how to do it in 2 equations.  

equations:

a = b-5

c = 2a

a + b + c = 69

to reform the distraught soviet union, the democratization of the communist party was promoted through party secretary mikhail gorbachev's policies of “perestroika” and “glasnost.” perestroika refers to the reconstruction of the political and economic system established by the communist party.