Answer:

Explanation:
When teacher falls into the cliff then she shout for Help at the same time
so here we know that sound will go down and reflect back up
so here in 3 s distance traveled by the sound



now in the same time the distance that teacher will fall down is given as



now total distance traveled by teacher and sound in 3 s


this total distance must be equal to twice the height of the cliff


Characteristics help us to classify seeds because different plants have different features.
<h3>How are characteristics used to identify and classify plants?</h3>
The divisions classify plants that are based on whether they reproduce by spores or seeds. Spore-bearing plants include ferns, club mosses, and horsetail while on the other hand, Seed-bearing plants are divided into gymnosperms and angiosperms. Different plants have different characteristics and features so on the basis of these characteristics we can easily classify seeds whether they belong from angiosperm and gymnosperm.
So we can conclude that characteristics help us to classify seeds because different plants have different features.
Learn more about seeds here: brainly.com/question/18799172
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Answer:


Explanation:
m = Mass of proton = 
v = Speed of proton = 0.5c = 
Circumference of the colider is 7 km


Centripetal acceleration is 

Force on protons is 
Yes, in general, metalloids are slightly reactive.