<span>the one that is not a factor that contribute to natural selection is : Population stability
population refer to the capability of a community to maintain its total amount of organisms within a specific period of time.
This has nothing to do with natural selection, which basically a nature's way to reduce the number of organism to findout which organisms are more adaptive</span>
Answer:- The natural abundance of 
is 0.478 or 47.8% and 
is 0.522 or 52.2% .
Solution:- Average atomic mass of an element is calculated from the atomic masses of it's isotopes and their abundances using the formula:
Average atomic mass = mass of first isotope(abundance) + mass of second isotope(abundance)
We have been given with atomic masses for and as 150.919860 and 152.921243 amu, respectively. Average atomic mass of Eu is 151.964 amu.
Sum of natural abundances of isotopes of an element is always 1. If we assume the abundance of as n then the abundance of would be 1-n .
Let's plug in the values in the formula:
151.964=150.919860n+152.921243-152.921243n
on keeping similar terms on same side:
negative sign is on both sides so it is canceled:
The abundance of is 0.478 which is 47.8%.
The abundance of is = 
= 0.522 which is 52.2%
Hence, the natural abundance of is 0.478 or 47.8% and is 0.522 or 52.2% .
Answer:
See explanation
Explanation:
Matter may exist in three phases; solid, liquid and gas. The state in which matter exists depends on the extent of intermolecular forces operating in the substance.
In solid particles, the molecules that compose the solid are close together because the molecules of a solid do not move from place to place but they continue to vibrate about their fixed position.
For liquids, the molecules that compose a liquid are in random motion but are less energetic than molecules of a gas.
In gases, the molecules are not held together at all. The molecules of a gas have the highest degree of freedom. They move from one point another at a high velocity.
Hence, the order of increasing degree of movement of the particles in different states of matter = solids<liquids< gases.
Solids have well arranged particles, the molecules of a liquid are a little more disorderly than liquid particles while gas particles are the most disorderly of all the states of matter.
I think both of them are but I really don't know
