Alright kiddo, let me explain it to you in a very simple way.
An infraspecific name is like a nickname for plants and animals. Just like how you may have a nickname like "Buddy" or "Sweetie", plants and animals have them too.
You know how a dog is a type of animal, but there are many different breeds of dogs like a German Shepherd or a Golden Retriever? Well, each breed has their own infraspecific name, kind of like their own nickname.
So, in the same way, plants and animals that belong to the same species can have different infraspecific names based on their physical differences. For example, a rose can have different varieties or cultivars like the "Peace" rose or the "Queen Elizabeth" rose. These are like the infraspecific names for these different types of roses.
In summary, infraspecific names are like nicknames or extra names that help us identify different varieties or types of plants and animals that belong to the same species.