Can someone me asap what is a reason that fossil fuels are often used as an energy source? animals and plants are not affected by their usage. beneficial byproducts are created from their combustion. there is an unlimited supply of them in the ground. they are relatively inexpensive and easy to produce.

Which changes of state do the labels represent? a: b: c:

In a hydrogen molecule there are a total of four charges, 2 protons in the two nuclei, and 2 electrons. how many unique charge-pairs are there (without double counting)?

You have a resistor and a capacitor of unknown values. first, you charge the capacitor and discharge it through the resistor. by monitoring the capacitor voltage on an oscilloscope, you see that the voltage decays to half its initial value in 3.00 ms . you then use the resistor and capacitor to make a low-pass filter. what is the crossover frequency fc?