Jellyfish serve as a model for bioengineers for the same reason yeast were once so valuable to geneticists: they're simple to deconstruct.

People with anxiety disorders such as OCD know that nothing can be more paralyzing than having too many options. Go to a store to buy a sweater, find four that you like and the odds are pretty good you'll stare and stare... and buy nothing at all.

There are a lot of obstacles in the way of our understanding animal intelligence - not the least being that we can't even agree whether nonhuman species are conscious. We accept that chimps and dolphins experience awareness; we like to think dogs and cats do. But what about mice and newts? What about a fly? Is anything going on there at all?

Everybody loves to spend money at least some of the time - because everybody loves the stuff you can buy with it. The key to the pleasure level of any transaction is the balance between the pain of the payment and the reward of the purchased object.

Toxins love to get you while you're young. Lead, mercury, secondhand smoke and sundry other environmental nasties do a lot more damage when tissue is immature, vulnerable and growing than when it's mature and comparatively fixed.

There are popular celebrities, there are unpopular celebrities and then there are the walking dead. You know the walking dead when you see them: they look like Mel Gibson, still striving for drunken charm in an L.A. County mug shot, after getting picked up on a DWI charge that included anti-semitic slurs directed at the police.

Scarily, football helmets, which do a fine job of protecting against scalp laceration and skull fracture, do little to prevent concussions and may even exacerbate them, since even as the brain is rattling around inside the skull, the head is rattling around inside the helmet.