213,000 can be rewritten as 2.13*10^5. This tells us that it has has 3 significant digits.
Your correct answer is b. It has three significant figures.
Canals are man-made, meaning, they are Human Systems.
Faults are natural, meaning, they are <span>Physical Systems.
Floods are not created by man, meaning, they are </span>Physical Systems.
Bridges are man-made, meaning, they are Human Systems.
I hope this helps!
<span>The question says, which three groups were helped by the Social Security Act? They correct option is C. Social security Act was enacted to take care of their elderly, then unemployed people and their disabled in their society who are unable to take care of their daily financial needs.The Act makes financial provisions for their basic needs.</span>