Answer:
The answer is B.
Step-by-step explanation:
The correct answer is B an element. An element is a substance that can not be broken down into other substances. They are made up of a single type of atom.
A compound is a combination of two or more elements that are combined to form a core complex substance. An example of a compound is water which is made up of hydrogen and oxygen (two elements).
An organ is part of an organism composed of tissue which itself is made up of cells that performs a function in the organism. e.g. a liver, heart, lungs.
And an organism is a thing that has living characteristics such as reproduction, growth, and development that requires energy, composed of one or more cells. e.g. a frog, a human, a kangaroo.