In describing a vector, what must you describe besides the magnitude?
O A. Its direction
O B. Its a scalar quantity
O C. Its length
O D. Its resultant

Direction

Explanation: A vector is a geometrical representation of physical quantity. It has a particular direction with a specific magnitude. In the geometry of space whether it is two dimensional or three dimensional the vector quantity has a specific direction. Such as a stone is thrown with a velocity in a particular direction.
The path of the stone in three-dimension shows its direction and speed is its magnitude.
Hence, the velocity of stone has two property magnitude mentioned as speed and particular direction. On writing the mathematical expressions for vectors, it is denoted by arrow mark on its top as shown below.

The independent variable would be the fertilizer as it is what the dependent variable (the growth of grass) depends on.