Answer: half life
Explanation: Radioactive decay follows first order kinetics and the time required for the decay of a radioactive material is calculated as follows:
t= time required
k= disintegration constant
x= amount of substance left after time t
a= initial amount of substance
when one half of the sample is decayed, one half of the sample remains and t can be represented as 
at 
, 
Radium and polonium is the answer to this question. I hope I helped out!
Answer:
No.
Explanation:
The reason comes the <em>Law of Conservation of Mass</em>.
In an ordinary chemical reaction, <em>you cannot create or destroy atoms</em>.
So, you must have as many atoms at the beginning of a reaction (in the reactants) as at the end (in the products)
We use this principle to balance chemical equations.
For example, the equation for the formation of water from hydrogen and oxygen is
2H₂ + O₂ ⟶ 2H₂O
There are four atoms of H and two of O both before and after the reaction.
Answer:
Its the first one. The cells are arranged for structure.
Explanation:
Animal cells do not need to maintain a shape since out bodies do it for us. Plant cells need something for structure.
