What does the melting point of a solid indicate?

$A$ student heats a beaker containing ice and water. He measures the temperature of the content of the beaker as a function of time. Which of the following graphs would correctly represent the result? Justify your choice.

$(a)$ Enumerate the changes that take place in a liquid during evaporation.
$(b)$ How is the rate of evaporation affected by changes in the following? Justify your answer.
$(i)$ Temperature
$(ii)$ Wind speed
$(iii)$ Humidity

Which of the following will cause more severe burns and why?
$(a)$ Steam at $373 \, K$
$(b)$ Water at $373 \, K$

Look at the figure and suggest in which of the vessels $A$,$B$,$C$,or $D$ the rate of evaporation will be the highest? Explain.

Which state of matter is found to be more stable at lower temperatures?