Using current technology, useful parallax measurements can only be found for stars up to about 340 light years (100 parsecs) away.
None of the choices is correct.
If two runners take the same amount of time to run a mile,
they have the same average speed. But their velocities
are not the same unless both runners begin and end their
run at the same points.
Speed is (distance covered) divided by (time to cover the distance).
Velocity is not. It's something different.
'Velocity' is not just a bigger word for 'speed'.
Answer:
Atoms found in nature are either stable or unstable. ... An atom is unstable (radioactive) if these forces are unbalanced; if the nucleus has an excess of internal energy. Instability of an atom's nucleus may result from an excess of either neutrons or protons
I believe the last time the dead bird count was updated (12/16/16), there is a count of 1,350 dead birds. There is 1,350 dead birds from 33 countries have tested positive for WNV in 2016.
