The most commonly observed two-headed animals are turtles and snakes.

It is most usually observed in the part of the spinal cord corresponding to the neck area.

The survey was restricted to mammals, the species most reliably observed by park scientists and visitors.

Health risks are the most easily observed and can be the most expensive.

Roosevelt elk are the most readily observed of the large mammals in the park.

It is one of the most closely observed storms ever, its eye was studied for research.

Parkfield is the most closely observed earthquake zone in the world.

It is one of the most widely observed Jewish holidays.

But this time most observed the command of the Intifada leadership not to participate.

It is now the world's most widely observed secular holiday.