Answer:
c.Ionic bond is formed between two metals or two non metals.
I believe the answer to this question is cellular respiration
3. naturally occurring
4. fossilized plants or air bubbles ( probably the plants tho)
5. increased
6. the green house effect occurs naturally, it is being polluted both naturally and unnaturally, the unnatural pollution is contaminating our 'greenhouse" and that is horrible.<span />
Answer:
C. Can't be observed directly
