Grasslands have trees..

a.) along streams
b.) in summer only
c.) throughout their area​

sodium i think the chemical element of atomic number 11, a soft silver-white reactive metal of the alkali metal group.

c. heat from the poles back down towards the equator.

they had the law tat factories that produces smoke cannot be built near residential buildings.

building of proper sewage system was done to ensure that the waste is carried away from the humans so that they do not get diseases from it.

also they built water systems to provide water in those areas which are drought prone.

c.           is the correct answer