Answer:The frequency of the echo is slightly decreased
Explanation:
Given
speed of boat 
cliff is
away
when boat is still , suppose t is the time taken by the echo to reach observer on the boat
But as soon as boat starts moving the distance between cliff and boat decreasing and time for echo to reach observer also decreases
and we know 
therefore frequency of the echo slightly decreased.
Slightly raising your body temperature while increase oxygen and blood circulation throughout your body
Answer:
there are 7 significant figures
Explanation:
15.33879+15.555
=30.89379
there are 7 significant figures
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Answer:
the similarity is that hands are applied and force