Which of the following is a replacement reaction? A )4Al(s) + 3O2(g) ↔ 2Al2O3(s)
B) 2C4H10(g) + 13O2(g) ↔ 8CO2(g) + 10H2O(g)
C) Mg(s) + 2HCl(aq) ↔ H2(g) +MgCl2(aq)
D) CaCO3(s) ↔ CaO(s) + CO2(g

< > according to newton's third law of motion, forces always act in equal but opposite pairs. another way of saying this is for every action, there is an equal but opposite reaction.< >

1. a)c-14 has two more protons

2. d)they have different numbers of protons, neutrons, and valence electrons; they are all gases at room temperature.

3. c) iron and nickel.