A biological system is a complex network of biologically relevant entities. ... Examples of biological systems at the macro scale are populations of organisms. On the organ and tissue scale in mammals and other animals, examples include the circulatory system, the respiratory system, and the nervous system. source: google
Answer: Classification\
Explanation:
Classification is the arrangement of organisms into orderly groups based on their similarities. In order to classify an organism, a biologist must use a system that groups organisms according to shared characteristics and their relationships between one another.
Answer:
You can only see it in December through March
Explanation:
The Canis Major can only be seen during the Winter season.
Coal contains sulfur and other elements, like dangerous metals (mercury, leads, and arsenic) that get into the air when coal is burned. Burning coal releases particulates and cause an increase in air pollution, it also emits the amount of CO2 (carbon dioxide) in the atmosphere