An electric circuit is anything in which electric current flows. Typically it refers to things with wiring like the electronics in your phone, but it can be made of anything that conducts electricity.
Say you have a battery, it basically has a bunch of electrons under a potential (think of gas in a tank under pressure), but the only way for the electrons to move is to move through a conductor, which are molecules with loosely held electrons. If you take a copper wire and touch each end to the two terminals you’ve completed an electric circuit because the electrons can now flow. But you can also put things partway through the wire like a lightbulb, which when the electrons run through it generates light.
I think the correct answer from the choices listed above is option D. Scientific theories summarize patterns found in nature. Although, the statement scientific theories are never proven is somewhat true. They are either disproved or they are never disproved. Hope this answers the question.
Most reactions are exothemic. If the forward reaction of an equilibrium reaction is exothemic then the reverse reaction must be endothermic.
If a system in equilibrium is heated, it will move in exothermic direction to give out heat energy.
The planet MARS is visible without a telescope on many clear nights. The planets JUPITER, MERCURY, VENUS and SATURN are also viewable without the aid of magnification.
