you can. you can use a trimmer to generate an analog signal, use the adc to convert the analog signal to get a digital reading of the wiper's position, and use that to control how long you want a port to be set, or cleared. viola! you have your own pwm.As you will see, the ADC (understood as Analog to Digital Converter) may not play a part in doing PWM to control a LED.
Since Art History requires research I don't think it would be an ideal course choice.Is it time to consider a switch to Art History?