Answer: a vector
Explanation:
A Vector is a physical quantiy that has can magnitude and direction. Examples of vectors are Velocity, acceleration, force, momentum etc
Now, since velocity is defined as the displacement experienced by an object in a specified direction, it is therefore correct to call velocity a vector
B - They have different arrangements of atoms.
Adrenaline, Cortisol, Norepinephrine.
Explanation:
Tests for gases
Hydrogen, oxygen, carbon dioxide, ammonia and chlorine can be identified using different tests.
Hydrogen. A lighted wooden splint makes a popping sound in a test tube of hydrogen.
Oxygen. A glowing wooden splint relights in a test tube of oxygen.