Question:
In your body, what two organs work together to make sure that oxygen gets to all the other organs of your body?
Answer:
Heart and lungs
Question:
Why should plants be included in investigations about the water cycle?
Answer:
Plants are part of the water cycle through the process of transpiration.
Question:
If a neutral atom loses an electron, what is formed?
Answer:
An ion
Question:
This in turn causes the average temperature on Earth to rise. Which of the following observations supports that theory?
Answer:

Carbon dioxide in the upper atmosphere absorbs and re-emits heat radiated from Earth's surface.