There is no planet heading towards Earth. All the planets have well defined orbits. and will not impact each other in the foreseeable future.

Cougars typically have a positive impact on humans as they are an essential part of the food chain. These large cats are normally fearful of humans, heading the other way when they see one, eliminating any negative impact.

a sub heading is a heading that breaks down a subject into sections

The prefix for the word 'heading' is 'un-'.

pause at each new heading to make sure your notes are complete.