A piece of metal. I believe it is a piece of metal.
Answer:
Let's say a horse. In it's environment biotic factors such as predators and other animals that the horse competes with for food are limiting factors. Abiotic factors are the amounts of water, the temperature, and precipitation are also limiting factors.
1 volt = 1 joule per coulomb.
Current doesn't actually pass 'through' a battery.
But if it did, then each coulomb would gain or lose 6 joules in traversing 6 volts, depending on its sign, and whether it climbed or fell.
The right answer is
2) NaCl
In fact, from the definition of acid, all acids contain at least one atom of hydrogen. In the options given by the problem, all compounds contain at least one atom of hydrogen H, except for the NaCl: therefore, NaCl is not an acid.