Answer: To know if a document is a primary source, check to see when the document is published, if it is an autobiography of a person, a diary, a letter, or the documents happen at the time of the event.
The competition between two organisms can be seen if there is only 1 source of food or habitat space and they're competing against each other for the food or habitat.
There is cooperation between two organisms if they are helping each other with resources or alarming each other if there is danger.
Predation between two organisms happen when one organism hunts the other organism for food.
Answer:
The vascular system
Explanation:
The human blood circularitory system can be used to explain capillary action in the human body, our heart pumps blood in and out with no use of external forces.
I need more points. That's why I am awnsering this, sorry.