Question

question
definition of atomic mass
most abundant isotope of carbon on earth
atomic mass of carbon
definition of mass number

Explanation:

Step1: Recall atomic - mass concepts

Atomic mass is the average mass of all isotopes of an element, taking into account their relative abundances. The mass number is the sum of protons and neutrons in a single isotope.

Step2: Identify correct definitions

The most abundant isotope of carbon on Earth is Carbon - 12. The atomic mass of carbon (12.012) is the average mass of all carbon isotopes.

Answer:

Definition of atomic mass: Average mass of all isotopes
Most abundant isotope of carbon on Earth: Carbon - 12
Atomic mass of carbon: 12.012
Definition of mass number: Number of protons + number of neutrons