Why are floods in urban areas particularly dangerous?
a. city buildings do not allow flood waters to recede
b. flood waters spread pollutants and diseases more rapidly.
c. flood waters permanently damage crop soils.
d. most cities are built in flood zones.

Why is the huronian supergroup rock formation particularly interesting to scientists? because it looks like a cross-section of a giant, stone encyclopedia because it formed during the period when oxygen began to accumulate in the atmosphere because it contains unusually large amounts of oxygen and sulfur because it dramatically altered the planet's development when it first formed