1. Is A. at the poles because thats where the magnetic field is going out then coming back into the earth to produce the magnetic field.
2. Again its A. because the compass needle is attracted to " north " which is magnetic south. It does this because opposites attract.
3. This one would be B. Because if the magnets were being repelled the magnetic field lines would look like there was a line that the field hit and bounced off of it.
4. This answer is A. the magnetite helps them migrate so they know which way is north and which way is south.
5. This answer is A. Because without the domains there wouldn't be poles on the magnetic object. <span />
Answer:

Explanation:
For this case we have the following info given:
Number of Na+ ions 
Each ion have a charge of +e and the crage of the electron is 
The time is given
if we convert this into seconds we got:

Now we can use the following formula given from the current passing thourhg a meter of nerve axon given by:

Where N represent the number of ions, e the charge of the electron and Q the total charge
If we replace on this case we have this:

And from the general definition of current we know that:

And since we know the total charge Q and the time we can replace:

The current during the inflow charge in the meter axon for this case is 
Answer:
electromagnetic waves
Explanation:
"wave" is a common term for a number different ways in which energy is transferred
Answer:
41.4 g
41.4 cm³
1.08695 g/cm³
Explanation:
= Density of water = 1 g/cm³
Mass of water displaced will be the difference of the

Mass of water displaced is 41.4 g
Density is given by

So, volume of bone is 41.4 cm³
Average density of the bird is given by

The average density is 1.08695 g/cm³