(ENVIRONMENTAL SCIENCE QUESTION, PLS ANSWER ASAP, 14 PTS) Do you think the mix of energy sources used in our region is appropriate? Should it be changed? Why or Why not? Prove 2 pieces of evidence to support your reasoning.
(I need a short essay of this)

Aresistor with an unknown resistance is connected in parallel to a 9 ω resistor. when both resistors are connected in parallel to an emf source of 21 v, the current through the unknown resistor is measured with an ammeter to be 4 a. what is the resistance of the unknown resistor? answer in units of ω.

As the distance from a magnet increases, what happens to the magnet force?

The illuminance of a surface varies inversely with the square of its distance from the light source. if the illuminance of a surface is 120 lumens per square meter when its distance from a certain light source is 6 meters, by how many meters should the distance of the surface from the source be increased to reduce its illuminance to 30 lumens per square meter?