How, if at all, did the Mongols differ from the peoples that they conquered?

The sun a. will become a red giant within two to three million years b. is in its main sequence, which willlast thousands of years c. is in its main sequence, which will last billions of years. d. will explode as a supernova after its main sequence

We're always up for a good laugh, but, seriously, refrain from posting silly or answers. keep the quality of high by following the rules and posting thoughtful answers.

Which of these is a disadvantage of hydrogen fuel cells? a. engines that use hydrogen fuel are more efficient than gasoline-powered engines. b. the only emission produced by hydrogen fuel cells is water. c. hydrogen fuel is continually available and useful for heating. d. hydrogen fuel is often purified in a process that emits lots of greenhouse gases.