Can someone help me with this test question pls (8th grade science)

15 km/h

Explanation:

If it takes 30 minutes to run 7.5 km/h if you double the time to 60 minutes (an hour) 7.5 doubled is 15.

i'd say that the moon rock is about 2.2 billion years old.

i'm thinking (a) to keep sand in place; ////////////

explanation: a sand fence or sandbreak, like a snow fence, is used to force windblown, drifting sand to accumulate in a desired place. sand fences are employed to control erosion, sand dune stabilization, keep sand off roadways, and to recruit new material in desert areas.