Why and how do lizards grow back separated tails?

Now this is another interesting one from May issue of Discover. It's realli quite a coincidence tt my last two posts is about animals too..hehe..The red ones are the more interesting ones..okay so here goes: "Losing a tail is a significant event in a lizard’s life. Herpetologists refer to the process as caudal autotomy (caudal relates to “tail” and autotomy to “casting off a body part”). It is considered an antipredatory adaptation since it is effective at confusing a predator. Although the chance of attacking the tail versus the head is often described as fifty-fifty, many species have brightly colored tails, and they will wag them back and forth to increase the likelihood that a predator will target the tail. When attacked, a lizard releases its tail either by direct trauma or sometimes before it is even touched. The detached tail wiggles with a nervous spasm, distracting the predator long enough for the lizard to escape. The specific mechanism that allows the tail to be released evolved early in the history of lizards. Lizard tail vertebrae have a perforated fracture plane encircling the bone. When a tail is broken, the vertebrae break along the fracture plane, and overlying muscle and connective tissue separate as the tail falls off. Over time, trauma to the vertebrae induces dormant cells to activate, and the tail will regenerate with an underlying tube of cartilage rather than separate vertebral bones. While the ability to lose and regenerate the tail may save a lizard’s life, it isn’t without costs. Should a lizard be attacked twice, it is advantageous to have a regrown appendage. However, tail regeneration is energetically expensive and can also result in lowered social status. Still, it is better than being someone’s dinner."

How do flies walk on the ceiling?

Sorry for not posting anything..been quite busy..so now here's an interesting one from Discover :How do flies walk on the ceiling?" I would highlight some of the interesting points in red: 'In addition to tiny claws, flies have specialised adhensive pads on their feet called pulvilli. These are covered with minute hairs that are between 2/10,000 and 2/1,000 of an inch long, each with a flattened tip. Scientists speculated that because they were curved, flies' foot hairs must be tiny hooks, latching onto microscopic irregularities in surfaces. "Hairy" adhensives in other organisms such as beetles, spiders, and geckos were postulated to work the same way. Later, research showed that such hairs were flexible and didn't behave like hooks at all. Many animals adhered strongly to both smooth and rough surfaces. Scientists discovered that flies and beetles secret a sticky fluid over their feet, which seems to act like a glue. The feet of spiders and geckos, in contrast, are pefectly dry, which suggest these animals employ intermolecular forces to adhere to various surfaces. Such observations leave us with more questions. Why, for instance, would lightweight flies need glue to stick to the ceiling, which much heavier animals like geckos don't? And how do flies detach once they've "glued" themselves to a surface? We won't understand the true nature of how flies actually walk on the ceiling until these questions are answered.'