1. So that even if one path is down as isn't working, the other paths will keep on working. That is crucial to buildings, and it will prevent a blackout. But in a series circuit if one path is down, there will be a blackout.

2. Beause the wires have high resistance, and if they have high resistance, the more the resistance the more the heat. It will increase in a direct porpotional way.

A1. When we use parallel circuits instead of series circuits, than we have more than one path on which the charge may flow. So, if one bulb burns out, unlike the series circuits, the other bulb will continue to glow. Of course, there is a disadvantage in paralle circuits, too. The light of a bulb is much dimmer in parallel circuits than in series circuits. But, the circuits in building and homes are usually made into a parallel circuit, so even if one bulb, or electrical devide is switched off, the other devices can still be used.

A2. A heating element is a coil of wire in which produces heat by  an electric current. The heating element is made up of a type of wire that has a very high resistance. Generally, as the temperature gets hotter, the resistance gets higher too.

1. There are two reasons that people use parallel circuits instead of series circuits in buildings and  homes. The first reason is that if people use series circuits, and switch off one object, the rest of the electrical devices that is connected will be switched off, too, because there is only one path and the path is cut off. Meanwhile, if we use a parallel circuit, we can use the rest of the electrical devices even though we turn off one. The second reason is that as we add more electrical devices to a series circuit, the less current is available to a device. But because each device we add in a parallel circuit has its own branch to the power source, the devices work to their fullest.

2. I think it is because if there is high resistance in a wire, the electrons that are supposed to move among the atoms will hit the atoms with immense speed and produce heat energy due to friction. High resistance means more obstacles, leading to more collisions and more heat energy. For example, copper has low resistance, so is often used  in wires that need high speed and less heat energy, but iron, which has higher resistance than copper, is often used in things such as toasters, which need to transfer electricity into heat energy.