I need help with this plz

If 1 km = 0.621 miles, how many miles are in a centimeter

The speed of a falling object increases at a constant rate as time increases since the object was dropped. which graph could represent the relationship betweent time in seconds, and s, speed in meters per second? speed of a falling object object over time

Ammonia molecules have three hydrogen atoms and one nitrogen atom.how many of each atom arein five molecules of ammonia