In order for heat to flow there must be... * A. identical tempatures
B. a difference in tempatures
C. a difference in altitude
D. an electrical current present

If a hydrogen atom is neutral, it must also have  one electron. an oxygen atom (o) has an atomic number of eight (8). this means a neutral oxygen atom has eight protons and eight electrons. the element actium (ac) has an atomic number of 89, so it has 89 protons and 89 electrons in a neutral atom

Matter- occupies space and possesses rest massno matter is the opposite