Answer:
protons
Explanation:
An element, by definition, always has the same number of protons. Sodium, element 11, has 11 protons. Anything with 11 protons is a sodium atom, regardless of the number of neutrons, electrons, or politicians.
The mass decay rate is of the form

where
m₀ = 3000 g,the initial mass
k = the decay constant
t = time, years.
Because the half-life is 30 years, therefore

After 60 years, the mass remaining is

Answer: 750 g
Adenine pairs with Thymine and Guanine pairs with Cytosine. I remember this by the car (C) goes in the garage (G). Then A and T are the only ones left, so they pair together.