Hello, Thanks for making your post on brainly!
I would say the best answer is C)Mixture
A mixer is made by combining 2 or more elements, but your not making a new element. And there are no chemical reactions happening to make a new element.
Hope this helps. Have a great day.
Radioactive is the most penetrating nuclear radiation
It is B because horn coals are bigger and I read it in a book
The daughter isotope (a decay product)of O-15 = N-15(Nitrogen 15)
<h3>Further explanation
</h3>
Radioactivity is the process of unstable isotopes to stable isotopes by decay, by emitting certain particles,
- alpha α particles ₂He⁴
- beta β ₋₁e⁰ particles
- gamma particles γ
- positron particles ₁e⁰
O-15 emits positron particles ₁e⁰, so the atomic number decreases by 1, the mass number is the same
Reaction

The mass number of the daughter isotope = 15, atomic number = 7
If we look at the periodic system, the element with atomic number 7 is Nitrogen (N)
Answer:
Forming the activated complex requires energy.
Explanation: