Answer : 
Explanation :
It is given that,
Charge, 
Velocity of Aircraft,
(in west)
Magnetic field,
( in north )
Using the relation as :

Magnetic force is ,


Using Right hand thumb rule, the direction of force is in the plane perpendicular to the velocity and the magnetic field i.e.
.
Definitely the last one, brain stem
The nitrogen fixation is the process of conversion of nitrogen gas into a usable form.
Answer: Option 3
<u>Explanation:
</u>
The nitrogen fixation is the process where the nitrogen gas present in air gets trapped and converted into ammonia or other nitrogenous compounds. This is the first step of nitrogen cycle.
The atmospheric nitrogen will get absorb in soil and gets converted to either ammonia which acts as nutrition for plants or other nitrogen related compounds which acts as fertilizers.
So, the nitrogen which get converted to usable stable form of nitrogen compounds can be used by plants, microorganisms and other organisms in the ecosystem.