America's age = 243.85 years
<h3>Further explanation</h3>
When converting units, list and multiply all the units until you find the unit you want
Time unit conversion
1 year = 365 days
1 day = 24 hours
1 hour = 3600 s
7.69 x 10⁹ seconds to years :

(a) 9.8 m/s/s
This never changes.
Answer: I don’t really know
Explanation:
I don’t know sorry
Answer:
Stalagmites
Sinkholes
Stalacites
Explanation:
These features are created because the ground water dissolves solid rocks and move the solid rocks, dissolve solutions beneath the ground water gradually and therefore enlarging the cracks, which eventually form a cave. Ground water carries minerals which are then deposited and can form stalagmites or stalactites. If a stalactite and stalagmite combine together, they usually form a column.