I'm not sure what the answer choices are, exactly, but looking up the question I found several other questions with answers, so I'm guessing based on those the choices would be:
1) physical barrier within population
2) extensive gene flow
3) chromosomal changes within population.
Which, in this case, the answer would most likely be 3) chromosomal changes within population.
Eubacteria is a right answer
They are inherited by dominant genes or traits from the parents.
Answer:
Helium
Explanation:
We know that this atom has two positive particles on the nucleus (protons) with two neutral particles (neutrons). We can also see that it hass two electrons on the orbitals. Knowing this, we can say that the element is Helium.
Helium has a relative atomic mass of 4 and it's atomic number is 2. The atomic number is equal to the number of protons and electrons the atom has, and the atomic mass can be used to calculate the number of neutrons:
Relative atomic mass = Neutrons + atomic number
So we know that:
Neutrons = relative atomic mass - atomic number
Neutrons = 4 - 2 = 2.
