Describe an instance where you might use standard rounding. Describe an instance where you might use order of magnitude estimation. I need help on this plz! I’m running out of time. If you did this too plz help me out!

When applying kirchhoff's rules, one of the essential steps is to mark each resistor with plus and minus signs to label how the electric potential changes from one end of the resistor to the other. the circuit in the drawing contains four resistors, each marked with the associated plus and minus signs. however, one resistor is marked incorrectly. which one is it?

The ph is the a.independent variable b.the dependent variable c.control group

Uwill get answer it brainliest will be awarded for →calculate the pressure exerted by a body having a mass of 30kg over an area of contact 400cm2.also explain it for every step there should be