Answer: Option D) there are no holes for blood to enter or leave the system
The human cardiovascular system is considered closed because there are no holes for blood to enter or leave the system
Explanation:
The closed circulatory system are made up of blood vessels called arteries from the heart that branch into small units called capillaries but eventually join up with other blood vessels called veins that are connected to the heart. So, blood is always confined to circulate within the blood vessels and the heart as there are no holes for blood to enter or leave the system
Thus, the human cardiovascular system is considered closed
The cell theory consists of the rule that all living things must contain cells. The stuffed animal (since it is nonliving) has no cells. More evidence to prove this is that the stuffed animal comes from a manufacturer not other cells.
Answer:
C
Explanation:
Carbon dioxide molecukes leave the body in exchanged air and oxygen molecules enter the body in inhaled air.
False. An echo bounces off walls. Soft materials are put on walls of music studios so that the room does not echo.
So they can design ......experiments so "B' would be a good answer or "c"
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