delicate

However, the F protein has a delicate structure that changes rapidly from a "pre-fusion" form to a "post-fusion" form when the viruses fuse with cells.

He opted for deals over delicate diplomacy and often put a price tag on America’s friendships.

It’s 10 tons at least, far longer than it is tall, its seemingly endless neck and tail held parallel to the ground in surprisingly delicate balance.

"Given the delicate nature of this we are not in a position to comment any further," said McNulty.

It hosts a major American air base and has handled many delicate political negotiations, including with Iran, the Taliban and Russia.