The colour we see is a measure of the wavelengths of light nor absorbed by the cloth. We would call the colour of the cloth blue if it absorbed longer wavelengths of yellow/orange/red. Sunlight contains all the visible wavelengths. Whatever is not absorbed is reflected.
Energy is the capacity to do work. Energy exists in various forms in the entire universe.
It may be light,sound,electric,magnetic,kinetic,potential,thermal energy etc.
As per the law of conservation of energy, it is neither created not destroyed. It can change from one form to another form.The total energy of the universe is always constant.
The process in which energy will change from one form to another form is called energy conversion.
There is also another terminology for energy conversion called energy transformation.
Energy transference is the process in which energy will be transferred from one body to another body.
Hence the correct answer to this question will be conversion and transformation
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.
There is not enough information to draw a conclusion about