How do plants obtain nitrogen?
a-they remove it from the air.
b-they absorb it through their roots.
c-they fix it in their leaves.
d-they produce it in their stems.

B. They absorb it through their roots

Explanation:

When nitrogen is released in the air plants cannot remove it through the air directly. They have to absorb it through another part of the plant. With that being said they have to absorb it through there roots.

explanation:

the universal gravitation equation. since the gravitational force is directly proportional to the mass of both interacting objects, more massive objects will attract each other with a greater gravitational force. if the mass of one of the objects is doubled, then the force of gravity between them is doubled.