Growth in the building of canals was made possible by: A. Production of reliable maps.
B. Improvements in engineering methods.
c. Improvements in steam engines.
D. Agreements with railroad companies.

B. Improvements in engineering methods.

2018 means 2018 ce or common era

there have been other eras too including bce, which included way more years.

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.