How did the temperature relate to the “recommended temperature limit” (solid horizontal red line)? Will give extra points for right answer or explanation

The “recommended temperature limit” represents limit of the temperature that is good for our world.

Explanation:

The temperature related to the “recommended temperature limit” means that in the graph there is a limit of temperature for our world's environment. if the temperature is between this limit, there is less or no adverse effect on our environment while on the hand, if the temperature exceeds from this limit, then it adversely affected our world because the emission of carbondioxide gas in the atmosphere increases due to this increase temperature..

because the light is a great source of energy for the plants to survive. (i hope this )

idk what the options are but

these is a strong electrostatic attraction between the ions hence a lot of energy is needed to overcome this attraction

this is why the boiling points are so high