A graph of real speed can have a section that's as steep as you want,
but it can never be a perfectly vertical section.
Any vertical line on a graph, even it it's only a tiny tiny section, means
that at that moment in time, the speed had many different values.
It also means that the speed took no time to change from one value to
another, and THAT would mean infinite acceleration.
The Ozone layer is responsible for the absorption of harmful
radiation from the sun before it hits the surface or exterior structure of our
planet. It is known to be a belt of a known occurring gas, known as “ozone”
which is sealed around the Earth’s atmosphere. It serves as a shield, which absorbs
most of the sun’s ultraviolet radiation.
Answer:
caves are mainly formed by water or in some other cases limestone.