What is meant by a biological system

Which sentence best describes the relationship between chlorophyll and the chloroplast? a.)chlorophyll is a chemical found in a chloroplast. b.) chloroplast is a chemical found in a chlorophyll. c.) both chlorophyll and chloroplasts are found in animals. d.) both chlorophyll and chloroplasts make carbon dioxide.

Which kind of worm has a closed circulatory system? a planarian b fluke c pinworm d an earthworm

Which of the following human activities resulted in the growth of the north american deer population?