Answer:
In my opinion ...it is option A:)
<span>Chemical properties, such as density, must be observed when a substance is in its natural state at room temperature and normal atmospheric pressure.</span>
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 />
The answer is a im pretty sure
Might be gene regulation, the process of turning genes on and off in normal development
