Answer:
D. as you move down the structure, there are fewer organisms in each group.
Step-by-step explanation:
When we move down from kingdom to species, the number of organisms decreases because more closely related organisms are placed down the group. There are fewer kingdoms that have a large number of organisms in it and has less similarities among them and when we move down, the number of organism decreases in number and at the end there are few organisms are present in it which is more closely related to each other.