Help me it’s timedWhy did the Chinese construct the Grand Canal? O to increase trade between the north and south
to improve irrigation for greater food production
to protect from nomadic invaders from the north
O to connect to trade with other countries and cultures

It was build I order to easily ship grain from the rich farmland to southern China to the capital city of Beijing

the answer to fill in the blank in this question would be the word resource, it is defined as the money, material or people (since human resource is a very valuable good) that a company or a person has at disposition (meaning they can use the resource as they see fit), to be able to complete a task or achieve a goal.  

the causes of the dust bowls were severe droughts,   lands became dry and hard, temperature was higher than usual, hot and dry conditions killed crops, high winds. because of those factors, the winds kicked up dry soil and created clouds of dust.