Answer:
A Elements
Step-by-step explanation:
The substances on the periodic table are examples of elements. 
An element is a distinct substance that cannot be split-up into simpler substances. Such substances consists of only one kind of atom. 
There are over one hundred elements that are known to date. 
- The periodic table arranges the elements based on the periodic law. 
 - The periodic law states that the properties of elements are a periodic function of their atomic number.