The answer is: D.unstable nuclei emitting high-energy particles as they formed more stable compositions.
Those high-energy particles are alpha particles
, beta particles
, gamma radiation.
For example, the decay chain of ²³⁸U is called the uranium series.
Decay start with U-238 and ends with Pb-206. There are several alpha and beta minus decays.
Antoine Henri Becquerel (1852 – 1908) was a French physicist and the first person to discover evidence of radioactivity.
Becquerel wrapped fluorescing crystal (uranium salt potassium uranyl sulfate) in a cloth, along with the photographic plate and a copper Maltese cross.
Several days later, he discovered that a image of the cross appeared on the plate.
The uranium salt was emitting radiation.
Because of this discovery, Becquerel won a Nobel Prize for Physics in 1903, which he shared with Marie Curie and Pierre Curie.
Reactants are what make up the product.
Answer : The molarity and molality of the solution is, 18.29 mole/L and 499.59 mole/Kg respectively.
Solution : Given,
Density of solution = 
Molar mass of sulfuric acid (solute) = 98.079 g/mole
98.0 % sulfuric acid by mass means that 98.0 gram of sulfuric acid is present in 100 g of solution.
Mass of sulfuric acid (solute) = 98.0 g
Mass of solution = 100 g
Mass of solvent = Mass of solution - Mass of solute = 100 - 98.0 = 2 g
First we have to calculate the volume of solution.

Now we have to calculate the molarity of solution.

Now we have to calculate the molality of the solution.

Therefore, the molarity and molality of the solution is, 18.29 mole/L and 499.59 mole/Kg respectively.
Answer:
x-10 should be the answer