Give reasons.
A stone thrown upward returns back to the earth surface.

Gravity

Explanation:

Due to earths gravity, anything that goes into the air returns back to the surface unless it is given the ability to fly.

Hope this helps!

d

explanation:

v=uf/(u-f)

= 5.10/(5-10) convex lens has positive focal length

=50/-5

=-10 cm (formed at other side)

show the wavelengths of a wave. show the crests of a wave.