1.   He and colleagues in Israel have discovered a naturally- occurring compound within the body which mimics the effects of cannabis on the brain.

2.   As for methyl bromide, a naturally occurring compound, the scientific community has reached no consensus on its role in ozone depletion.

3.   OH is a naturally occurring compound that helps clean many pollutants in the lower atmosphere.

4.   Because the naturally occurring compounds cannot be distinguished from the hormones in untreated animals, treatement cannot be detected, he said.