1. 100,000% A. I simply googled C12 and it's the most stable Isotope of Carbon...
2. A as well.. 99% sure.. and so far my 99% sure has been 100% correct so ... :p
Centripetal acceleration is given by the formula

Since we know the value of the acceleration is 9.8 m/s² and we know r, we can solve for the speed, which is the magnitude of v. Note the value of a is just the acceleration due to gravity, which is what makes the rocket orbit and not fly off into space.
The answer is A sorry i would of expalined why but i have to go :c
Answer: informative array
Explanation:
"The periodic table of elements arranges all of the known chemical elements in an informative array. Elements are arranged from left to right and top to bottom in order of increasing atomic number. Order generally coincides with increasing atomic mass. The rows are called periods."
https://www.livescience.com/25300-periodic-table.html
Answer:
please do not trust those scam links