<span>An eon is a geologically around tens of millions of years. A period is a million year included in an eon which is also made up of several eras. Therefore my answer is a period due to it being a subset of an era which is a subset of an eon.</span>
In April of 1869, he obtained a patent for one of his most important inventions, the air brake. This device enabled trains to be stopped with fail-safe accuracy by the locomotive engineer for the first time and was eventually adopted on the majority of the world's railroads
Example picture for a valley
Explanation:
A valley formed by flowing water, called fluvial valley or river valley, is usually V-shaped. The exact shape will depend on the characteristics of the stream flowing through it. Rivers with steep gradients, as in mountain ranges, produce steep walls and a bottom.
No because they help middle and low developed only
Answer:
From UV rays from the sun
Explanation:
Because UV rays are dangerous
