Lack thereof? Is it a typo? Should be "there of"? 1. Sounds like he was issuing a warning about climate change, mass extinction and other negative human impacts on our only planetary home. A warning we should heed, regardless of religious affiliation or lack thereof. Lack thereof? Is it a typo? Should be "there of"? 2. The researchers also found that the clamshell and fire deposits stabilized the ridges and protected them from erosion. No such stable ridges exist along the coast from the past 400 years, after the local people died from disease or war, or were pushed inland. Any incipient ridges since were easily toppled by wind and storms. "Any incipient ridges since were easily toppled by wind and storms." Can I say "Since any incipient ridges were easily toppled by wind and storms."? 3. The researchers plan to investigate that possibility for human teeth, both baby and adult. But until then, chew carefully. And don’t lead with your chin. What's the meaning of "don’t lead with your chin."?