The answer is (a) because movement is acceleration
A decrease in it's operating temperature would make a heat engine less efficient. This is because in order to operate, a heat engine needs to be hot and maintain that temperature.
If the ground is flat, and both bullets are released at the same time from the same height, then they both hit the ground at the same time.
The horizontal motion of the one from the gun has no effect on its vertical motion.
Electricity is a form of energy. Electricity is the flow of electrons. All matter is made up of atoms, and an atom has a center, called a nucleus. The negative charge of an electron is equal to the positive charge of a proton, and the number of electrons in an atom is usually equal to the number of protons. Hope this helped. ;)
