Answer to this is Radioactive isotopes.
Isotopes are the species of the same element having different atomic masses that means the number of protons remains the same but number of neutrons do differ. For example
and
are the two isotopes of Hydrogen (
).
Radioactive isotopes are the isotopes which release some kind of energy in the form of alpha particles, beta particles or gamma radiation. Examples of each of the decay processes are :
Alpha Decay: In this decay one alpha particle having atomic mass 4 and atomic number 2 or we can say a He molecule will come out. 
Beta Decay: In this decay a
particle is emitted increasing the atomic number of the reactant by 1 unit.

Gamma Radiation: In this type of reaction only radiation is emitted out which does not change the original molecule.

Increase the force they are using to move the box by adding more helpers
Explanation:
If you want to increase the speed that the box is moving, increasing the friction would make it more difficult, decreasing the force they are using would just make it slower and increasing the angle of the ramp would make it harder. Adding more people would make it easier. “The more the merrier”
Answer:
82.24% percent composition of N and 17.76% percent composition of H .
Explanation:
K₂CrO₄(aq) + Ba(NO₃)₂(aq) = BaCrO₄(s) + 2KNO₃(aq)
2K⁺ + CrO₄²⁻ + Ba²⁺ + 2NO₃⁻ = BaCrO₄ + 2K⁺ + 2NO₃⁻
spectator ions: K⁺, NO₃⁻
<span>Water:
*can dissolve most substances
* contains dissolved minerals
*expands when it freezes</span>