Answer:
Diversity: When many different ideas/opinions/races/religions etc. are present.
Equality: The right of different groups of people to have the same rights and be treated the same.
Inclusion: The act of including something as a part of skmething else. Also the idea that everyone should be able to use the same facilities and enjoy the same experiences, no matter race/religion/disability or other minority.
Discrimination: Purposefully treating a group of people differently (and worse) because of their race/sexual identity/sexuality/religion etc.