Answer:
The Gestalt principle is known as closure.
Step-by-step explanation:
Gestalt is a branch of Psychology and it centers on the idea that an individual tends to look at something as a whole, as more than just the sum of its parts. This is how an individual organizes his/her perceptions.
Closure is the principle which best explains this phenomenon. It means that a certain shape can be perceived as a whole even when a part of it is missing. This is because the brain tends to "close" and finish objects, for example.
Even when parts of a shape or picture are missing, we are able to see it as a whole, filling that visual gap.
In this case, Leo has designed the 5 petal shapes and the stem. Even thought the center is missing, the brain has enough information to "close" the shape and understand that Leo's logo is a flower.