Describe two technologies that humans have used to overcome environmental challenges in dubai. (paragraph needed)

DUBAI — Dubai’s skyline is the most sparkling in the Middle East. But down on the ground, the environmental problems of a quickly erected city built on sand look a lot less alluring.

In the last year, tourists have swum amid raw sewage in Dubai’s slice of the Persian Gulf. The purifying of seawater to feed taps and fountains is raising salinity levels. And despite sitting on vast oil reserves, the region is running out of energy sources to support its rich lifestyle.

The simple basics of waste treatment and providing fresh water, in addition to running major industrial projects, require so much electricity that the region is turning to a nuclear future, raising questions about the risks, both environmental and political, of relying in part on a technology vulnerable to accidents and terrorist attacks.

Dazzled by Dubai’s rapid urbanization, other countries in the gulf are seeking to emulate it, especially as they prepare for a population boom. Dubai offers a cautionary tale in the pitfalls of building metropolises in the parched desert.

“Growth has been so intense and enormous, but people forgot about the environment,” said Jean-François Seznec, a Middle East expert and professor at Georgetown University in Washington. “The attitude was, business comes first. Now, they are seeing increased problems, and they realize they have to be careful.”

i am not sure :)

the answer would be the third option, "no, ariel should have added 9^2 and 12^2 and compared that to 15^2."

this is found through the pythagorean theorem, which is a^2 + b^2 = c^2.

this is the correct way of solving the problem:

9^2 + 12^2 = 15^2

81 + 144 = 225

225 = 225